What's next in aeronautic connectivity and sensing?

Since the graphene discovery, its applications to electronic and optoelectronic devices have been intensively and thoroughly researched. The extraordinary and unusual electronic and optical properties allow graphene and other two-dimensional (2D) materials to be promising candidates for infrared (IR) and terahertz (THz) photodetectors. Quantity of published papers devoted 2D materials as sensors is huge. However, authors of these papers address them mainly to researches involved in investigations of 2D materials. Up till now, the first test to estimate their place in wide infrared detector family was given in Advances in Optics and Photonics 11(2), 314 379, 2019. In the present paper this topic is treated comprehensively with including both theoretical estimations and many experimental data. In the paper, at the beginning we describe shortly fundamental properties of graphene-based materials and alternative 2D materials, and performance of detectors fabricated with them. Next, the position of 2D material detectors is considered in confrontation with the present stage of infrared and terahertz detectors offered on global market. A new benchmark, so-called "Rule 19", used for prediction of background limited HgCdTe photodiodes operated near room temperature, is introduced. This rule is next treated as the reference for alternative 2D material technologies. The performance comparison concerns the detector responsivty, detectivity and response time. Final conclusions predicts place of 2D material-based detectors in the near future, in wide IR detector family.

This paper investigates measurement methods of frequency converters' phase noise transfer function. The typically used instrumentation and setups quantifying absolute and residual phase noise are discussed first. We identify the possibility of extending the functionality of single-channel signal source analyzers by estimating the device's transfer function. The test results of proposed technique are given.

In this paper, we propose that optical Bloch oscillations-Zener tunneling is observed in stacked metal fishnet waveguide arrays. The analogy of Bloch-Zener tunneling, which is the dynamic behavior of electrons in solid under an external field, is achieved. The spoof surface plasmon polaritons by structured surface and near fields coupling between adjacent layers of metal waveguide arrays induce the optical Bloch-Zener tunneling. The effect can be predicted and demonstrated by the dispersion relationship.

The finite element method is one of the most commonly used numerical methods for solving Maxwell's equations in the computer-aided design of microwave components. However, its accuracy comes at the price of the high computational cost and therefore fast optimization involving full-wave finite element simulations is still a big challenge. One of methods to speed up the optimization process is parametrized model order reduction (PMOR). In this approach the initial projection basis is generated only once, in the offline phase, and then it is reused in subsequent optimization steps for any set of geometry and material parameters. In this work we show how to improve the quality of PMOR by enriching it with a few vectors that are computed by applying a few iterations of a preconditioned conjugate solver with deflation.

This paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order to verify the validity of the method, several examples have been investigated and compared with other numerical techniques.

In this paper, concepts of fractional-order (FO) derivatives are analysed from the point of view of applications in the electromagnetic theory. The mathematical problems related to the FO generalization of Maxwell's equations are investigated. The most popular formulations of the fractional derivatives, i.e., Riemann-Liouville, Caputo, Gruenwald-Letnikov and Marchaud definitions, are considered. Properties of these derivatives are evaluated. It is demonstrated that some of formulations of the FO derivatives have limited applicability in the electromagnetic theory. That is, the Riemann-Liouville and Caputo derivatives with finite base point have a limited applicability whereas the Gruenwald-Letnikov and Marchaud derivatives lead to reasonable generalizations of Maxwell's equations.

The problem of electromagnetic (EM) wave scattering for a homogeneous material supplemented by a set of thin wires is studied by an asymptotic method. The electrical components of the full EM field are presented in an explicit form. The refraction coefficient (RC) of resulting inhomogeneous material is derived as result of solving some auxiliary integral equation. The computational results testify that new inhomogeneous material is characterized by specific RC that can acquire the negative values.

In this contribution, a new genetic-algorithm-based method of searching for roots and poles of a complex function of a complex variable is presented. The algorithm employs the phase analysis of the function to explore the complex plane with the use of the genetic algorithm. Hence, the candidate regions of root and pole occurrences are selected and verified with the use of discrete Cauchy's argument principle. The algorithm is evaluated in electromagnetic benchmark that successfully solves the eigenvalue problem determining the propagation of surface waves along a spatially dispersive graphene sheet. The numerical results show that possibility to find all roots and poles of the function may be limited by the initial population size, especially when the search region is large and roots and poles are located close to each other.

This paper proposes a new calibration method for vector network analyzers, and the method uses one thru calibration standard and two short calibration standards. We name this new calibration method "Thru-Short-Short" (TSS) calibration method. The algorithm of the proposed method is derived in this paper in detail. At the same time, the experimental results are used to prove the accuracy of the TSS calibration method. When we calibrate the vector network analyzer with this method, the fixtures at both ends are fixed, and they do not need to be moved. It is very convenient for the scenarios that the fixtures are not easy to move. The validity and accuracy of the proposed method are verified by experimental results of measuring the permittivity of a slab of Teflon.

Work presented in this paper is a part belonging to a micro-Doppler detection project. Global aim of the project is to develop processing algorithms and waveform designs suitable for the human-originating micro-Doppler detection. Purpose of this work was to develop an auxiliary tool for the analysis. To simulate signals and processing properties in terms of micro-Doppler detection, a proper model of a scattering object, with particular emphasis on the properties of human tissues, was needed.

In this paper, algorithms for simulation of the wave propagation in electromagnetic media described by fractional-order (FO) models (FOMs) are presented. Initially, fractional calculus and FO Maxwell's equations are introduced. The problem of the wave propagation is formulated for media described by FOMs. Then, algorithms for simulation of the non-monochromatic wave propagation are presented which employ computations in the time domain (TD) and the frequency domain (FD). In the TD algorithm, the electromagnetic field is computed as a convolution of an excitation with Green's function formulated based on an improper integral and the Mittag-Leffler function. On the other hand, the FD algorithm transforms an analytic excitation to FD, executes multiplications with phase factors, and finally transfers back result to TD. This algorithm involves elementary functions only, hence, computations are significantly faster and accurate with its use. However, applicability of the FD algorithm is limited by the sampling theorem. Numerical results and computation times obtained with the use of both algorithms are presented and discussed in detail.

In future 5G mobile networks the radio over fiber (RoF) links will gain wider application due to its simplicity, flexibility and elasticity. In these links single drive Mach-Zehnder modulators are used for intensity modulation. However, these modulators produce not only intensity modulation but also incremental phase modulation which is a challenging problem because that effects the signal transmission. The other challenging problem is caused by fiber dispersion. Therefore fading of the detected signal is obtained at specific fiber lengths. However, applying combined double intensity and phase detection the received signal variation is reduced significantly. The transmission of digital signals is also influenced by fiber dispersion causing pulse broadening and this way inter-symbol interference which limits the bit rate. In this paper the modulation and propagation problems and their effects on signal transmission quality are investigated achieving this way optimum solution.

In this article, a new meta-heuristic method of searching for roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of a complex function. The method initially generates two uniformly distributed populations of particles on the complex plane and extracts the function phase in a position of each particle. By collecting phase samples, the candidate regions of root and pole occurrences are selected. Then, the second and subsequent populations iteratively explore candidate regions and decrease their size. Because subsequent swarms are generated globally during the iterations, an area outside a candidate region is thoroughly explored, eliminating possibility of root or pole omission. The algorithm is verified in electromagnetic benchmark that solves the equation determining surface waves on a microstrip antenna. The numerical results show that the algorithm is able to solve multimodal problems quickly even with a small initial population and a small number of generated swarms.

This paper overviews the process of prototyping of corporate feeds for excitation of linear arrays of low sidelobe broadside sum patterns. Although the corporate feeds of interest produce non-uniform in-phase excitation tapers at their outputs, they comprise only equal-split power dividers and thus shorten the feed implementation stage, simplify the corporate feed composition, and reduce sensitivity of the feed elements to tolerances of manufacturing and material parameters. A summary of the selected results with the emphasis on low sidelobe levels is presented. The levels are computed using the array factor and provided for feeds driving linear arrays of up to thirty elements. It is should be emphasized that the array characteristics at the feed prototyping stage are irrelevant to the feed-array implementation technology and, in this sense, are similar to characteristics of filters' prototypes. The outline of the dedicated software package developed in Matlab used for feed prototyping is overviewed. An example of feed implementation in microstrip technology with electromagnetic simulations for the upper part of the K-band is presented. The considered class of corporate feeds as well as the feed prototyping tool considered in this work can contribute to the development of cost-and performance-efficient communication solutions for sub-mm wave and mm-wave frequencies.

In this paper a novel design of broadband reduced-length directional coupler for planar and MMIC applications has been presented. The proposed component utilizes two indirectly coupled-lines sections realizing the same coupling coefficient connected with uncoupled transmission-lines. To verify the correctness of the proposed design method, a 3-dB planar directional coupler for 1 GHz center frequency has been designed, fabricated, and measured. Moreover, a monolithic version of the considered solution has been designed for fabrication in the monolithic OMMIC D01PH GaAs technology, operating at 24 GHz center frequency.

In the paper, outputs of the sensitivity analysis performed for a 60 GHz circularly polarized antenna array is presented. The analysis identifies dimensions and positions of coupling slots between layers, dimensions of patches and the width of waveguides as critical. Precision of manufacturing technologies has to be better than 0.1 mm to obtain acceptable parameters of the whole array.

In this paper a rotating coupler is presented that can be used for signal transmission on fast rotating shafts. Rotating couplers may be necessary especially in big industrial halls where, due to more and more transmitters around 2.45 Ghz, the industrial, scientific and medical (ISM) band of many radio standards, the channel can be too crowded to reliably transfer safety critical information. The concept of the here presented coupler is to be low-cost and splitable that it can be attached around a shaft even without the disassembly of the entire machinery.

We investigated operation of microwave sensors for detection of objects floating on a river. Three types of sensors with different operation principle were chosen for testing: FMCW perimeter radar, microwave barrier and monostatic Doppler detector. During tests, selected objects (boats, packages and swimmers) repeatedly flowed across a 45-m wide river. The purpose of the study was to determine the probability and range of detection for various external conditions and the detector-object distances.

Nowadays indoor localization is getting more and more attention as there is a considerable growth in the interest for the indoor location-based services (LBS). There are several different techniques that allow for the calculation of the position of objects and people inside the buildings. Methods utilizing measurements of the received signal strength (e.g. WiFi or BLE based) are most common but provide accuracy of roughly 2-3 meters. Recently, ultrawideband (UWB) technique is more often being considered for the indoor localization. It relies on the measurements of the time of arrival of received signals and allows for the calculation of the position with errors in the range of only dozens of centimeters. However, in order to work correctly, UWB-based systems require strict synchronization between the anchors that form the infrastructure. In the paper a novel method of wireless synchronization utilizing two reference nodes is presented. Synchronization method is described along with the explanation of the transmission scheme and discussion on the results of the performed experimental verification.

A planar antenna is designed to replace complex structures of many rat-races and 90° hybrids used in conventional target detection antennas. The proposed antenna has 2 x 2 microstrip patch antenna arrays with dual feeding to radiate symmetric polarizations in the 9.375 GHz (X-band). The sum pattern with circular polarization is implemented through a sequence feeding at port 1. The simultaneous feeding of port 2 radiates a difference pattern in all polarizations. Thus, a target detection antenna is designed with features that have fewer ports than the conventional monopulse antennas. The proposed antenna is compact, planar, and has a simple comparator circuit and equal sum and difference levels.

Single Frequency Networks are a popular solution in modern digital audio and television system networks for extending effective coverage, compared to their traditional single-transmitter counterparts. As benefits of this configuration appear to be obvious, this paper focuses on the exact analysis of, so called, SFN gain - a quantitative effect of advantage in terms of the received signal strength. The investigations cover the following aspects: the histogram analysis of SFN gain values and the SFN gain as a function of distance from the SFN geometrical distance. The analyses conclude with an observation that the most noteworthy contribution from the operation in the single frequency mode is observed on the far edges of the networks, whereas the least one close to the transmitters

Active Electrically Scanned Array (AESA) requires a diagnostic system that can consists of a set of external antennas for calibration of Transceiver Modules (TRM). In this paper, a microstrip patch antenna with wide beamwidth for such a system is presented. The manufactured antenna exhibits a 180º 6-dB beamwidth in C-band with matching better than -10 dB over a 10% bandwidth. It is shown that the use of the proposed antenna results in a reduced dynamic range of diagnostic coupling between the antenna and TRMs compared to antennas with the directivity of order of several dBi, thus the number of diagnostic antennas can be decreased and they can be placed closer to radar aperture boundaries. Furthermore, it is demonstrated that a low level of back radiation of the antenna leads to a diminished parasitic influence of radar construction elements on the desired coupling coverage.

The study of Class E amplifier operation modes with shunting filter as well as those of derived Class E/F3 and EF amplifiers with 0.33 duty ratio was performed. The goals of the experimental study was the reduction of maximum (over signal period) transistor drain voltage and reduction of the harmonic content in amplifier output. The normalized drain voltage in the range 2.2-2.35 at 90% efficiency was observed. The results can be used for high-efficiency amplifier design in the form of Integrated Circuits.

On the base of 2-plane discontinuity in microstrip transmission line the output networks for class-E/F amplifier with harmonic control are presented. The output network transforms high resistance of load into a low load resistance at MOSET drain. The harmonic filters are realized using coupled slot resonators of complex shape in ground plane of microstrip transmission line. Using this solution, the two output networks were designed and investigated: with control up to 3-rd, and up to 4-th harmonics inclusive. In the amplifier with 4-th harmonic control the drain voltage has flat waveform, which significantly increases transistor utilization factor. Efficiency of the both simulated power amplifiers at the operating frequency of 2.14 GHz was more than 80% at the output power level of 5.3-6.0 W.

Monopulse Comparator is one of the core components in development of RF front-end of the tracking radars and therefore widely employed in active phased array radars. Thus, active phased array system are progressively becoming the norm for airborne radars imposing stringent requirement on operation over a wide range of frequencies The proposed design employed four rat race couplers (180° hybrid coupler) to devise the monopulse comparator network and to exploit microstrip technology to realize the network. In this paper, an X-band Monopulse Comparator Network from 8 GHz to 11 GHz is realized on RT Duroid 6002 using microstrip transmission line technology. The design of the monopulse comparator network is modeled and simulated in ANSYS HFSS. The proposed monopulse comparator network achieved VSWR ≤1.6, and isolation values better than 20 dB for almost the entire frequency band.

A Ka-band compact 8-way power-combining amplifier is proposed by using parallel traveling-wave power divider with coplanar-arms magic-T. The coplanar-arms waveguide magic-T is applied to be the first dividing stage with compact size and great isolation. Two parallel dual-probe-coupling two-way traveling-wave power divider are applied to form a compact 8-Way divider with the measured insertion loss less than 2dB from 27-33.5GHz. The proposed divider is applied to a power combining amplifier. Its measured output power at 1dB gain compression (P1dB) is higher than 12.5 Watts, power-combining efficiency is from 74% to 93% from 27-33.5GHz. The whole size of the proposed structure is 60mm×40mm×25mm.

A concept of electrically small antenna for BeiDou BD2 B3 Chinese navigation satellite system was developed and studied. Three main miniaturized techniques: antenna loading by using high permittivity materials, making some part of antennas virtual by using ground planes and short circuits, and optimizing geometry have been employed in the design. Antenna performance was examined by experiments giving very promising results.

In this paper characterization of ferroelectric ceramic-polymer composites at microwave frequencies is presented. Tested materials are composed of barium strontium titanate (BST) and polyvinylidene fluoride (PVDF). The influence of three different shapes of ceramic particles is investigated. Measurement setup for determining the permittivity and tunability is described. Results show that the rod-like BST/PVDF composite has the best dielectric constant and tunability at 10 GHz with a value of 13 and 9% at 6 V/µm, respectively.

In this study, S11 at the front surface of the sample was measured in the frequency band of 0.50 to 3.0 GHz with various liquids in the jig after S11 calibration using SOM (short, open and reference material) conditions. The dielectric constant of the liquids was estimated from the above S11 based on 1. an inverse problem approach involving comparison with the S11 value calculated using electromagnetic analysis (known as the mode-matching method), and 2. an estimation formula involving comparison with termination associated with short, open and reference-material conditions. The Debye dispersion equation for calculation of methanol's complex permittivity was corrected from the results. The dielectric constants of various liquids were estimated using a formula for comparison with three reference materials (pure water, methanol and air) using methanol after dielectric-constant correction. The effectiveness of the proposed method was verified by comparing the above estimated values with otherwise obtained outcomes. Moreover, the S11 value of the jig was calibrated with short, open and another reference material (methanol) conditions after complex permittivity correction of methanol. The estimation results for the dielectric constant of pure water and similar after calibration were also compared with the above estimation values, and the reversibility of the proposed estimation method was verified. Favorable agreement of values estimated with each method was observed, indicating the validity of the proposed dielectric measurement procedure.

Ferromagnetic linewidth, g-factor and magnetic anisotropy measurements of mono- and polycrystalline yttrium iron garnet (YIG) spheres performed in a subwavelength cavity are reported, covering a frequency range of up to 28 GHz. Two factors influencing the apparent linewidth have been analyzed: the influence of the share of energy stored in the magnetic field to the total electromagnetic energy in the resonant system and conduction losses in the cavity walls. Additionally, two-port rectangular resonant cavity linewidth measurements at a few modes have been conducted. Good agreement between the two methods has been found. In the polycrystalline samples, the existence of the Buffler peak was identified, which is a non-Gilbert-type increase in the ferromagnetic linewidth vs. frequency dependence.

We investigate the impact of meniscus shaping the top surface of liquid samples tested in a semi-open cell applied to broadband permittivity measurements. We calculate the scattering parameters of the samples with flat and distorted surfaces using electromagnetic simulations done up to 18 GHz. The data are then processed using different methods for determining the permittivity. We compare the results of the Nicolson-Ross-Weir technique and our new meniscus removal method. This comparison clearly shows that the meniscus removal approach brings about smaller errors than the established NRW technique, particularly at higher microwave frequencies.

Low-loss dielectric laminates that are routinely used in manufacturing of printed circuit boards (PCBs) are known to be anisotropic. The in-plane and the out-of-plane components of the dielectric permittivity have been so far typically determined using several approaches. In this paper we performed measurements of both components of complex permittivity of selected isotropic and anisotropic laminar materials employing a combination of a few split-post dielectric resonators (SPDRs) and one cylindrical cavity supporting a few TM0n0 modes resonant frequencies of 2.45 GHz. No similar characterization campaign have been reported in the literature to the best of our knowledge

This paper deals with the description and evaluation of the M-sequence UWB radar system on chip (SoC). Instead of common 9 th or 12 th order M-sequence generator, the proposed UWB radar includes the 15 th order generator. Therefore, it has significantly longer unambiguous range and is able to exploit the regulatory spectral masks more efficiently. Consequently, it is better suited for sensing applications which require longer range and small dimensions of radar system. The theoretical assumptions are confirmed by experimental measurements in a simple measurement scenario.

The benefits of polarimetric radar technologies are addressed and respective technology gaps are identified for a variety of applications in radar and electronic warfare. Examples of fully polarimetric data processing are provided for FOPEN applications on real data, making use of Polarimetric Whitening Filtering (PWF) with subsequent Polarimetric Matched Filter (PMF) techniques as well as for Polarimetric Space Time Adaptive Processing (Pol-STAP) on simulated data. The performance advantages of these polarimetric approaches are demonstrated and compared with classical processing schemes. Part of these results were elaborated within the framework of the PolRad project, funded by the European Defence Agency (EDA), with the aim to demonstrate the benefits of polarimetric radar technology in defence scenarios for target classification, target detection and tracking of man-made object in vegetated environment as well as for the usability for Electronic Support Measures. Finally in this context a potential outlook is given in terms of technology and timelines for polarimetric applications.

The paper presents results of preliminary field trails of an FMCW (Frequency-Modulated Continuous-Wave) radar intended to use for border protection. A concept of the complete radar system as well as a detailed description of a developed low-cost radar demonstrator based on dual channel analog front end are presented. The field trials results obtained using the demonstrator are presented and discussed carefully in the paper.

The ground based mobile perimeter surveillance of many military and civil infrastructures to detect and track potential threatening targets on ground or in the air is still a very important capability of sensor systems. Such dangerous targets can be suicide attackers or drones, which violate the privacy of individuals or which can be used for spying, smuggling, or acts of terrorism. To demonstrate the possibilities of current technologies and processing methods, a high performance mechanically scanning surveillance radar sensor and a high-resolution camera were successfully combined for these applications. Both sensors have a high measurement update rate of up to 1.6 Hz. The most remarkable feature is the use of a 94 GHz radar sensor with 3D localization, georeferencing, extended Doppler analysis, RCS calibration and multi target tracking for stand-off monitoring in real-time of an area of interest. Furthermore, the real-time images of the multi-sensor system are transferred from the operator's computer to several mobile devices to disseminate an overview of the situation. The implementation of the real-time data processing and the real time data visualization plus the intuitive system control was done successfully. The stored radar and camera data can be used for the conservation of evidence, for further offline processing and for algorithm development.

In cooperation with the German Aerospace Center (DLR) the second Flight Trials of the Sense and Avoid Radar has been completed. The Radar has been tested within a fully capable Sense and Avoid System, which combines Cooperative Sensors such as ADS-B and T-CAS with Non-Cooperative Sensors such as Radar and Electro-Optics. Also the Airborne Weather Radar capability was successfully tested within the flight trials. Both functions work in parallel, which is facilitated by a sophisticated Radar Resource Management. This paper recapitulates the main design drivers of the radar and shows the test results of the Flight Test Trials regarding the Radar functions, which are in particular the Sense and Avoid Radar Function and the Weather Radar Function.

In December 2018 the European Commission approved a project proposal of four EU member states - France, Germany, Italy and the UK - to start an "Important Project of Common European Interest (IPCEI)" on Microelectronics. It will allow the national governments to spend about €1.8 billion as public support to the project partners for innovative research and development, and investment in first industrial deployment. This presentation will provide a short introduction into the IPCEI project and the five technology fields covered. The project's overall objective is to enable research and development of innovative technologies and advanced electronics components. The importance of R&D in First Industrial Deployment is for the five technologies is highlighted. Of special importance is R&D along the value chain chip-package-board/system. The mm-wave topics of the MIKON Focus Session is an example where the technology fields TF1 Energy efficient chips, TF2 power devices and TF3 sensors collaborate.

Today's SiGe heterojunction bipolar transistors (HBT) in BiCMOS technology environment enable the realization of highly integrated radar sensors for motor vehicles in the range from 76 to 81 GHz at reasonable costs. With fMAX values from 300 to 400 GHz and a fT in the range from 200 to 300 GHz, they form the basis for the wide use of safety-relevant automotive applications such as autonomous emergency brakes, collision avoidance or lane change assist, even in low-cost cars. SiGe HBT BiCMOS technologies therefore led to a strong boost, especially in the development activities for autonomously driving cars. The automotive radar as the first "mass market" for mm-wave technologies and circuits has increased investment in research and development in mm-wave technology considerably. Other, new and emerging mm-wave and THz applications will benefit enormously from this development. The development of SiGe HBT BiCMOS technologies with cut-off frequencies above 500 GHz is about to qualify and start of production. The use of higher operating frequencies and significantly shorter wavelengths enables new and very compact high-performance radar sensors with integrated antennas with high amplification. It offers significantly improved spatial, angular and Doppler (speed) resolution for future autonomous cars, gesture and environment detection in general, personal health monitoring and THz imaging and spectroscopy. The talk gives an overview of the development status of the next-generation 600 GHz SiGe HBT BiCMOS process from Infineon and illustrates the challenges and how they are mastered.

Silicon CMOS technologies have been advancing over decades, such that they start to enter the millimeter wave realm which has been traditionally dominated by BiCMOS and/or III-V technologies. In particular, Globalfoundries 22FDX® technology is a state-of-the-art planar CMOS technology that provides additional unique benefits from fully-depleted SOI for millimeter-wave and RADAR applications. It provides (1) transistors of fT > 350GHz and fMAX > 390GHz; (2) ultralow parasitic capacitances; and (3) novel back-biasing capability fully-integrated into SoC. In this talk, excellent device figure-of-merits will be presented for millimeter wave and RADAR transceivers. Specific features, such as relaxed-pitch, extended device-isolation from substrate, mmW Inductor, etc., are introduced as millimeter-wave enhancements. Finally, circuit demonstrators will be briefly discussed with a summary of 22FDX® platform outlook.

System-in-package (SiP) is a major trend in integration of microelectronic systems to tackle the increasing needs for more functionality into a smaller volume. SiP leads to heterogeneous integration of integrated circuits along with sensors, microelectromechanical components, passive devices, filters and antennas. Another important trend in packaging is the continuing move toward higher frequencies. 5G high-speed wireless communication, mm-wave radar for autonomous driving and high-resolution mm-wave environment sensing and imaging are just a few examples of applications for future markets. In this talk, we present the latest developments in packaging technologies for mm-wave radar and communication systems. We demonstrate the system integration capabilities of the embedded wafer level ball grid array (eWLB) technology. After introduction of low-loss transmission lines and high-quality planar inductors in thin-film redistribution layers (RDL), we present chip-package-board transitions without external matching networks optimized for use in the 60/70/80 GHz bands. We present the concepts of antenna integration in eWLB and show examples of different antenna structures. To demonstrate the system-in-package integration capabilities of eWLB, we show 60 GHz and 77 GHz eWLB transceiver modules with integrated antennas. The use of vertical interconnections and double-sided RDL extend the integration capabilities to the third dimension. We present ways of realizing vertical interconnections in eWLB using through encapsulate vias (TEV) and novel embedded Z lines (EZL) technology. We show examples of vertical interconnections, embedded passives, RF transitions and 3D antennas realized using the TEV and EZL technology. Finally we present the concept of substrate integrated waveguide (SIW) for eWLB. To combine advantages of planar circuits with rectangular waveguides we present a novel, compact and low-loss transition from chip to SIW in eWLB and to standard WR10 rectangular waveguide.

To evaluate the interaction between epilepsy-related brain activities and heart rate dynamics, we analyze electroencephalogram (EEG) and heart rate variability (HRV) using detrended moving-average cross-correlation analysis (DMCA) for pre- and postictal periods in subjects with focal epilepsy. The DMCA was applied to the 5 min. long periods of heart beat-to-beat intervals and power spectral density time series, located 5 and 10 min. before and after seizures. Statistically significant differences were found in the cross-correlation in (delta) (0.5-4 Hz) band for the periods before and after seizure, which shows the correlative coupling between RR intervals that (delta) band activity is changing while approaching to and after the epileptic seizure, that suggests the presence of nonlinear mechanisms of interactions between low-band EEG and RR intervals in observed periods of brain and heart activity in epilepsy. In contrast, no statistically significant changes could be observed while comparing brain-heart coupling in preictal periods. The wide scatter of distributions of all frequency bands in periods before epileptic seizure suggests that the multiscale cross-correlation coefficient is highly subject dependent and needs further subject-specific analysis for this particular period with longer time series.

The results of experimental studies on human verification by EEG signal analysis are presented in this paper. The developed approach was investigated using 220 EEG examinations recorded from 11 people, 20 examinations for every person. The first fifteen examinations were used for neural networks learning, and the rest 5 examinations for their evaluation. The EEG signals recorded for every person were separated into short segments for which feature extraction was conducted. After that, the features were introduced to a feedforward neural network, trained by the Levenberg-Marquardt backpropagation algorithm. We focused on spectral features, calculated separately for four EEG frequency bands. After the network training, we evaluated our approach by introducing at the network inputs the examinations from other days that were not presented to the neural network before. The results for two electrode sets: placed on the central (C3, Cz, C4, C3CzC4) and centro-occipital (C3, C4, O1, O2, C3C4, O1O2, C3C4O1O2), using accuracy, sensitivity, specificity, and precision measures, are presented and discussed in this paper. Regardless of the number of electrodes, almost all mean metrics were above 0.70 and increased with the number of electrodes from which the EEG signal features fed the neural network. One of the aims of this work was to investigate, whether temporary, daily changes in EEG signals would prevent people from being recognized.

The paper is devoted to development and studies on atrial fibrillation (AFib) detection in electrocardiogram (ECG) using digital signal processing (DSP) and machine learning (ML). The goal of this pilot study was to find the DSP and ML methods suitable for the AF detection in real-time in short single-lead ECGs containing 32 consecutive cardiac cycles. Three simple Heart Rate Variability (HRV) parameters from the time domain analysis were calculated and used as features for ML algorithms. Binary decision tree and shallow neural network were used for classification, and the impact of metaparameters on the performance of the AFib detection algorithms was investigated to determine the lower limit of their required complexity. In the neural network, different numbers of hidden neurons and different activation functions were examined. In the decision tree, different limits on the maximum number of splits were set. For both AFib detection algorithms, various sets of HRV-based features were tested. With neural network (two features, ten hidden neurons), 98.3% accuracy, 97.1% sensitivity and 99.1% specificity were obtained. With decision tree (two features, seven splits), 96.9% accuracy, 96.3% sensitivity and 97.4% specificity were reached. This study shows the usefulness of neural network and decision tree algorithms for the detection of atrial fibrillation using the simplest HRV parameters. The use of more complex HRV parameters in AFib detection with the proposed ML algorithms requires further investigation.

In recent years, a lot of headphones with active noise control systems have appeared on the consumer market. Most of these systems make use of specialized digital signal processors designed specifically to process audio signals in real-time. In this article, we present an active noise control headphone system based on the general use Raspberry Pi computer with ARMv8 processor and Linux operating system. This platform is not designed for performing realtime digital signal processing neither in terms of hardware nor software. But with the help of techniques such as multithreading and low-level audio programming in Linux, we created a real-time active noise cancelling system and compared it in terms of noise reduction with different commercial headsets.

In this paper, we propose an algorithm based on complex empirical mode decomposition with principle component analysis (CEMD-PCA) which estimates the vital parameters of stationary and moving person, irrespective of the orientation in an extreme clutter and multipath environment. The results obtained were compared against pulse oximeter(PULOX PO-300) and fitbit wrist band and the average error of heart beat was found to be less than 1%.

The 1st edition of the IGLUNA - a Habitat in Ice initiative and ESA_Lab demonstrator, run by the Swiss Space Center, was started in 2018 and concluded with a field campaign in June 2019 in Switzerland. A simulated lunar habitat, with a place for surface astronaut activities, was set up on the Klein Matterhorn, in and on the glacier. One of the experiments provided radio communication for the simulated astronauts - a successfully deployed longwave communication system allowed the crossing of the ice barrier between the habitat and the external environment, showing the utility and robustness of this technology in simulated space conditions. The achieved maximal signal range of 2077,06 km, with sufficient signal readability, presented the system as a widely-covering, which, including the very low consumed powers and relatively low total mass, shows it as a promising way of simple, reliable and direct communication for astronauts over a large distances on the Moon. During the conference presentation, many more information and data on the experiment are to be presented.

The paper includes a comparison of performance of two Kalman Filters: extended Kalman filter (EKF) and unscented Kalman filter (UKF) in a hybrid Bluetooth-Low-Energy--ultra-wideband (BLE-UWB) based localization system. In the system the user is localized primarily based on Received Signal Strength (RSS) measurements of BLE signals. UWB part of the system is periodically used to improve localization accuracy by feeding into the algorithm UWB packets time difference of arrival (TDOA). The proposed scheme is experimentally validated using two algorithms: EKF and UKF. The localization accuracy of both algorithms is compared.

This paper gives an overview about the BATS project, which aims to track the behavior of bats by developing an ultra-low power wireless sensor network. It is composed of an ultra-low weight sensor node which is attached to the animal and an extensive ground infrastructure for tracking the animals as well as remote data download of locally stored sensor data from the tags. The system achieves its low power consumption by adaptively enabling certain functions based on the current situation. The mobile node, as key component of the system, contains a variety of sensors, including an electrocardiogram (ECG) to allow precise insights in the animals behavior while maintaining a low weight of around 1g depending on the hardware configuration.

In this paper performance comparison of co-polarized and cross-polarized microstrip Van Atta arrays working in the 60 GHz frequency range is presented. They can be treated as simple chipless RFID tags with frequency response based identification. Tags with three different nominal resonance frequencies of 57, 62 and 67 GHz are designed by scaling optimized base model. Designed 62 GHz co-polarized and cross-polarized arrays with four interconnected pairs of elementary antenna arrays have small dimensions of 20 x 18 mm and 36 x 23 mm, and exhibit RCS levels of -20 and -22 dBsm, respectively. The influence of number of interconnected antennas on the radar cross-section (RCS) of the tag is investigated. Frequency responses of the tags are also examined and compared for both types of tags with 0.80 GHz (co-polarized) and 2.10 GHz (cross-polarized) 3 dB bandwidth of the RCS response at 60 degree interrogation angle.

High power microwaves (HPM) has destructive effect on electronic information system in the short distance, and which is mainly shown as jamming effect in the long distance. Aiming at the evaluation of interference effect of HPM on digital communication system in the long distance, this paper constructs the signal model of HPM jamming communication receiver, analyzes the relationship among bit error rate, jamming distance and duty cycle of HPM pulse. According to the demodulating principle of the communication receiver, the bit error rate (BER) of the communication system on different interference conditions is analyzed by Monte Carlo simulations. The simulation results show that the HPM has significant jamming effect on communication system over a long distance, which verifies the consistency between the theoretical analysis and the simulation results.

The European Spallation Source (ESS) is a next-generation neutron source, under construction in Lund, Sweden. An important requirement for ESS is to assure a precise phase synchronization of LLRF and Beam Diagnostics systems. They are operating at frequencies of 352.21 MHz and 704.42 MHz. The phase stability along the machine is provided by the phase synchronization system. The main part of the system is a Phase Reference Line (PRL). It is an entirely passive system based on a single coaxial rigid line located in the tunnel, which distributes both reference frequencies. A source of the reference signals is a Master Oscillator (MO) located in the Klystron Gallery. High power amplifiers used at each frequency provide a power level of about +50 dBm. The output signals are combined in a custom made diplexer. The two-tone signal is distributed to the tunnel by a single 7/8" coaxial cable. Ambient temperature variations and humidity changes in the tunnel, STUB, and Klystron Gallery cause the phase drifts in the phase distribution system. An active drift compensation system was necessary to reduce those phase drifts. This paper shows the concept and block diagram of the RF connection from MO to PRL.

FLASH, a soft X-ray free-electron laser facility, is currently subject to several ongoing and planned upgrade activities. The underlying control and synchronization systems also have to keep up with the changing requirements. Therefore, in order to provide improved performance and better maintenance experience, a new master oscillator system is proposed. Most significant improvement can be seen in the jitter performance, bringing sub-10 fs rms integrated jitter which is an order of magnitude better than the present system. The first parts of the system are expected to be operational in mid-2020, while the final system installation and commissioning are scheduled for the beginning of the year 2021.

A 6.27 GHz energy-efficient noise filtering class-F oscillator is designed in a 22 nm SOI CMOS process. A transformer-based resonator is adopted boosting the third harmonic of the fundamental wave and expanding phase insensitivity region in one oscillation period. The noise filter comprised of an inductor and a capacitor is used to reduce both the Q factor degradation of the resonator and the 1/f noise upconversion at the same time. Post-layout simulation results considering accurate 3D models for all relevant components proof an excellent phase noise of -127.5 dBc/Hz at 1 MHz offset drawing only 5.0 mW power consumption from a 0.8 V supply resulting in a figure of merit(FoM) of 196.4 dB.

We present a concept of a novel redundancy solution for the master oscillator of the European-XFEL facility. The solution implements automated switching between identical copies of the reference signal generation chains. The main difference from prior solutions is the ability to maintain a continuous reference signal also in the event of switching, e.g. caused by a failure in the system.

The development of an automotive surface recognition system is an important and yet unsolved task. In the current study we are considering a novel approach to surface classification based on the analysis of the image obtained using the Low Terahertz radar. The proposed experimental technique in combination with a deep convolutional neural network provides high surface classification accuracy.

Automatic Target Recognition (ATR) is one of the strongest growing technology topics, especially in commercial applications like image recognition and automotive. ATR applications in radars established in the fields of defence and protection stayed on a certain level for years, so today there is a strong need to participate in the performance growth enabled by modern technologies. In this paper the ATR potential of the Deep Learning (DL) approach is proved by comparing the performance of a highly mature "classical" concept using feature extraction and several types of classifiers versus several state of the art DL networks and training concepts. The comparison is done on the same large database of Micro Doppler signatures from several classes, as typically used for moving object classification and drone threat assessments. The comparison shows the benefit and potential drawbacks of the different approaches.

Sign language is the primary communication medium for the deaf-mute community. However, the literacy of understanding and using sign language is hard to gain without professional training. In this paper, we explore the use of low power frequency modulated continuous wave radar for automatic sign language recognition. The proposed system is composed of a radar, a sound cluster and a computer for transforming signals to spectrograms. Furthermore, as the time-frequency spectrograms are high-dimensional data with redundant information, we then perform dimensionality reduction by extracting the histogram of oriented gradients features from these spectrograms. The features are finally classified by the k-Nearest Neighbour algorithm and a classification result of 95.8% is achieved on the five testing signs. The impact of the k value in the k-Nearest Neighbour is also investigated.

In this paper an efficient wideband Direction of Arrival (DoA) and frequency estimation technique is presented which uses only a single snapshot from a multi-beam antenna array. The simultaneous spatial beams (beamspace) are generated by a Rotman lens which consists of a free-space true time delay network attached to a Uniform Linear Array (ULA) of broadband Vivaldi antenna elements. The proposed technique uses machine learning techniques to establish an optimal Neural Network (NN) configuration obtained with a training set. To improve the spatial and frequency space resolution a further estimation stage follows to the NN topology. This results in a lower computational load during the training phase and finally a very fast estimation of direction and frequency of the impinging signal. The performance is evaluated by measurements obtained in an anechoic chamber.

To prevent interference to other radio systems, the measurement and verification of unwanted emission levels, in the spurious domain and the out-of-band domain, are required for the radar systems. Since there is only one commercially available measurement site in the world capable of measuring unwanted emissions in the spurious domain and the out-of-band domain of a marine radar, more measurement sites are necessary. We are going to design and construct a measurement site in Japan. In this paper, we introduce the measurement site and propose how to control multipath propagation. There are three techniques to control multipath waves: narrow antenna beam width, diffuse reflection on the grassy ground, and the use of a reflected wave barrier. A method for estimating the reflection point is also proposed. It uses the interference fringes of the direct wave and reflection waves. The site insertion loss measurements are within +/- 4 dB of the theoretical site insertion loss of free-space.

Multi-beam antenna systems are the basic technology that is used in developed fifth-generation systems. This article is devoted to assessing the impact of a multi-beam antenna system on the interference level in the downlink. These interference are generated by neighboring base station antenna beams. The presented analysis is based on simulation studies in which the multi-elliptic propagation model is used. Transmission characteristics of propagation environments such as power delay profile and antenna beam patterns that define the geometric structure of the model were adopted on the basis of the 3GPP standard. The obtained results show the possibility of using the presented method to assess the separation angle between co-channel beams. It is the basis for minimizing spectral resources in the system.

Antenna arrays are used in many applications, such as space technology or long distance communications. However, there is often an issue of large antennas' sizes for such systems. For example, such a problem is urgent in wideband arrays. This is important because then the distance between antennas in the equidistant arrays cannot be hold. Thus the side diffraction maximums appear. Here we show that conversion to non-equidistant antenna arrays decreases radiation pattern's side lobes for direct radiation and deflection. Based on the methods in the manuscript, we reduced side lobes of our array to -10dB compared to the main lobe. These methods allow calculating non-equidistant antenna arrays with high accuracy using information about antenna's characteristics. Thus, the side radiation is decreased and the antenna array efficiency is improved.

Contemporary UWB positioning systems are able to provide excellent positioning accuracy. However, if the system is deployed in an environment where the propagation channel is demanding the positioning errors are significantly bigger. The paper contains a description of a method for correction of time difference of arrival measurement results. The applied offset corresponding to current tag location. Fingerprinting technique is used for correction data preparation and selection. The method efficiency was verified with measurements performed with UWB positioning system. The paper contains description of the proposed method. Results of experiments are included and discussed in the paper.

In this paper, the concept of direction of arrival (DoA) estimation using electronically steerable parasitic array radiator (ESPAR) antenna designed to operate in IEEE 802.11p vehicular communication standard has been investigated with respect to different possible elevation angles of a radio frequency (RF) signal impinging the antenna. To this end, two different possible sets of the 3D antenna radiation patterns have been used together with power-pattern cross-correlation (PPCC) algorithm and its extension that covers multiple calibration planes (PPCCMCP). Numerical simulations of the PPCC and PPCC-MCP angle estimation procedures at 5.89 GHz have been performed to verify the overall DoA estimation accuracies in the horizontal plane for different, and unknown at the moment of estimation, elevation angles.

In this paper, a 1x2 dual-band microstrip antenna array configuration in FOWLP technology for 5G applications operating in the 28 GHz and 38 GHz frequency bands is proposed. For the first time the antenna array is designed, simulated and fabricated on 200 µm mold substrate material for a compact 1 cmx1 cm Antenna-in-Package module. Results show a good correlation between simulation and measurement. A measured impedance bandwidth of 400 MHz is achieved at both 28 GHz and 38 GHz frequency bands, whereas the maximum antenna gain is approximately 6 dBi.

Heterogeneous integration leads to significant increase in design complexity. This complexity can be handled properly only by an enhanced design environment and extensive use of electronic design automation (EDA). It turns out that such a design system needs to be based on multi-dimensional modularization: modularization in configuration (like assembly design kits, so-called ADKs), modularization in data exchange and data storage (standardized file formats and data management), and modularization in design environments (even across company boundaries). We have developed a versatile, generic design flow environment, which enables the configuration of several ADKs in addition to a process development kit (PDK) for a complete chip-package-board design project. The content of an ADK has been aligned with the underlying set of EDA tools in the corresponding design flow. It needs to enable and support various steps in chip-package-board co-design: • Connectivity (schematic) entry • Concurrent layout design both in fully automated digital place-and-route as well as in full-custom manual style • Assembly design rule checks (DRC) • Overall connectivity checks: layout-versus-schematic (LVS) even across chip, package, and board domain • 3D model generation for subsequent package parasitic extraction and electro-magnetic field simulation We present a modular full-custom chip-package-board co-design environment based on a versatile backbone idea and a powerful concurrent layout environment, which has been applied successfully to various system-in-package (SiP) designs. We show design methodology challenges and the application of our co-design flow to RF and mmWave designs in fan-out WLP (FOWLP) or laminate BGA and LGA.

Consolidation of 4G LTE and 5G networks and emergence of 6G is calling for higher rates wireline and wireless connectivity solutions. This presentation will give an overview of the main high-rate links where mmW capable technologies are required. A review of associated addressable markets will be also discussed with some consequences in terms of Silicon process options. More detailed mmW technology description will be displayed concerning STMicroelectronics proprietary SIGe BiCMOS and CMOS on SOI process flavors giving an industrial answer to mmW challenges. Access to STMicroelectronics mmW capable technologies through Multi-Project Wafer production schemes within IPCEI on Microelectronics or European collaborative projects will be explained. Examples of circuit performances will be presented to illustrate the added-value in terms of speed, noise, power efficiency…Some advanced roadmap information will be disclosed about forthcoming process from STMicroelectronics as well as some insights on collaborative R&D projects in the scope of mmW to contribute in building European vision on mmW industrial future.

Millimeter-wave radar provides robust high-resolution distance, velocity, and angle information, as well as small-movement characterization. With the advent of low-cost semiconductor and packaging technologies that allow mass-producing millimeter-wave components, the widespread use of millimeter-wave sensors has started to become reality. Since the first introduction in the automotive area, radar has become a key sensing modality for driver assistance and automated driving. Here, a new generation of sensors and algorithms moves radar sensing from simple detection to classification and mapping. Additionally, new applications in robotics and consumer devices are starting to be realized. Small size, invisible integration, low-cost, and privacy are some of the advantages radars provide here. However, key for widespread adoption is a systems-approach that significantly reduces the application effort by using a single-piece digital-and-analog packaged component. Some obstacles to widespread adoption remain. Technical challenges include how to interpret and apply the sensor information to the given use-case, and low-power operation to make battery-operated devices feasible. On the non-technical side, world-wide harmonized frequency regulation remains a challenge.

Highly-Integrated Millimeter-Wave Frontends for Complex Radar Sensor Systems

Methods for estimation of the harmonic signal parameters with complex non-Gaussian interference are developed. Accuracy and robustness parameters estimations are investigated by Monte-Carlo technique.The modeling of the work of this processing methods is carried out.

The use of small and low-power general-purpose Software Defined Radio (SDR) receivers seems to be very attractive solution in a context of moving platform for multichannel RF signal acquisition, required in and Passive Coherent Location (PCL), passive SAR, and in digital beamforming. These receivers, however, are designed mainly for single channel operation and additional hardware components and software algorithms are required to perform coherent signal acquisition. A simple calibration procedure for time shifts and phase offsets, based on cross-correlation between the signals with superimposed training sequences, has been already presented as a solution. However, the results of processing the real signals acquired in the field have shown that this simple method cannot be applied in case of receiving strong signals from the antennas due to misleading phase offset estimates. In this paper, we propose a more advanced algorithm of estimation that employs matched filtering. This method has been validated by processing hours of four-channel recordings with DAB, DVB-T and FM broadcast signals prepared for PCL processing.

This paper presents a new concept of frequency modulated chaos shift keying system (FM-CSK) based on a modified Chua's circuit and chaotic synchronization. The proposed solution can be potentially used for communication systems in wireless sensor networks (WSN), where the physical security of data transmission, efficient modulation and demodulation, analog-digital and digital-analog conversion is of high importance. The mathematical model of the drive-response system based on a modified Chua's circuit, described by a system of four differential equations and nonlinear function, is a core of the offered communication system. The FM-CSK system concept is validated by MATLAB/Simulink simulation with a baseband additive white Gaussian noise (AWGN) channel. Approaches for the performance enhancement of the communication system are discussed and validated.

The use of binary and non-binary turbo codes to improve the performance of UWB data transmission with the use of complex wavelet signals with Phase Shift Keying (PSK) of different dimension is proposed. Simulation results demonstrating the efficiency of turbo codes used to improve the noise immunity of BPSK and 8PSK data transmission over the AWGN channel are presented.

A new approach to designing a hybrid filter bank (HFB) system has been demonstrated. The paper shows the relationship between the analogue analysis filter bank and its discrete equivalent counterparts. Equivalence conditions have been determined and a new method of approximation of filter characteristics has been demonstrated. It limits the number of FIR filter coefficients necessary to implement a synthesis filter bank. This is an extremely important aspect from a practical point of view, because it allows the implementation of a synthesis filter bank in programmable VLSI circuits. A rigorous method of testing the HFB system during a design process using dedicated band-pass signals has also been developed.

The dielectric properties of materials applied in advanced packaging technologies such as Fan-out Wafer Level Packaging (FoWLP) must be precisely known at mm-Wave frequencies for optimized package design. In this paper, the applicability of fork-coupled resonators for the electromagnetic characterization of an epoxy molding compound (EMC) for 5G applications is investigated by means of full-wave simulations. The analysis is experimentally verified by means of measurements of fabricated test structures on EMC (Nagase R4601-X65) material for 5G applications in frequency bands of 26.5-29.5 GHz and 37-40 GHz.

It is shown in this paper that a Fabry-Perot open resonator is applicable to the measurement of in-plane anisotropy of dielectric constant and loss tangent of laminate materials in microwave and mm-wave range. This is doable provided that linearly polarized TEM0,0,q Gaussian modes are exploited. Measurements are undertaken in an automated setup operating in the 20-50 GHz range and anisotropic thin PET foil is characterized.

The work proposes and validates a methodology for efficient imaging of material samples with a recently developed portable 2D scanner incorporating a 10 GHz split-post dielectric resonator and driven by a low-form-factor vector or scalar network analyser. First, experimental studies are conducted to evaluate the influence of the network analyser operating parameters on the accuracy and stability of complex permittivity extraction. The settings of 1 kHz intermediate frequency bandwidth and 200 frequency points within the measured band are selected, as a cost-to-accuracy compromise. Then, a post-processing procedure based on Lorentzian curve fitting is applied to the raw response, to further enhance the measurement accuracy and stability. The methodology is applied to three materials, and a 2D scan of a laminate sample demonstrates the achieved efficiency.

Homogeneous and inhomogeneous electromagnetic metasurfaces are designed to enhance the gain of patch antennas operating at 10 GHz. The metasurface consists of metallic split ring resonators, which can be fabricated with conventional printed circuit board technology on the top of a low loss substrate material. The metasurfaces are mounted above the patch antennas. It is shown by simulations and measurements that the gain of the metamaterial antennas at the operating frequency of 10 GHz have a threefold gain increase compared to the standalone patch.

This paper presents a 28GHz broadband low noise amplifier (LNA) with a fractional bandwidth > 32 % for 5G wireless communication systems. The LNA provides a very low noise figure, a high linearity and a compact size. These properties are essential in a 5G MIMO receiver front-end. The LNA is designed in a 130 nm SiGe BiCMOS technology and provides 24 dB gain at 28 GHz with a 3 dB-bandwidth from 21.4 to 30.6 GHz. The simulated noise figure at 28GHz yields 2.18 dB. An input-referred 1 dB-compression point of -13.0 dBm is reached with a DC-power consumption of 25.1 mW.

The paper investigates experimentally the effect of harmonic terminations on AlGaN/GaN power amplifiers (PA) performance at K-/Ka-band. Two technologies are compared, a 0.25um and 0.1um process. In both cases, a harmonic termination increases the achievable output power by about 10 % at the expense of bandwidth, whereas the efficiency is improved only in the first one.

This paper shows design and development of a highly integrated solid state power amplifier (SSPA) for new-space earth observation satellites. The SSPA operates in frequency range of 8.025 - 8.4 GHz with 20 Watt output power at input power range of -20 dBm to 0 dBm and power added efficiency (PAE) reaching up to 35 %. Although the main application of presented SSPA is earth observation (EO) it can be used in ground segment, e.g. for radar application as well.

This work presents a self-biased 2-stacked power amplifier cell that shows, between 33.5 GHz and 39.5 GHz (16% fractional bandwidth), an output power in excess of 33 dBm and gain and PAE above 6 dB and 27%, respectively. The cell has been developed on a commercial 100nm GaN-on-Si process, applying space derating rules at center frequency, where the output power is almost 33.8 dBm, the associated gain is higher than 7 dB and PAE is above 35%.

Sparse decomposition and l0 norm minimization approach to Synthetic Aperture Radar (SAR) image reconstruction is discussed. A linear frequency modulation (LFM) complex signal reflected from the earth surface, is decomposed by two-dimensional (2-D) multiplication of three matrices - azimuth Discrete Fourier Transform (DFT) matrix, image matrix and range DFT matrix. Image reconstruction procedure based on l0 norm minimization is applied to reduced number of measurements defined by randomly generated azimuth and range sensing matrix. The geometry of the scene is described by a two-dimensional surface function. The sparsity of the surface is achieved by multiplication of the surface function with a random binary matrix. Results of numerical experiments are provided to illustrate the suggested approach and to prove the correctness of the algorithm.

Inverse Synthetic Aperture Radar (ISAR) exploits the motion of the target to achieve cross range imaging, as opposed to its range resolving capability (along line of sight) which relies on the bandwidth of the signal. In ISAR imaging, it is usually the case that the relative motion between the radar and the target of interest is unknown. The lack of precise knowledge of this relative motion affects the quality of the reconstructed image. Therefore, estimating the relative motion is an essential step for ISAR imaging. Compared to the two dimensional ISAR, the three dimensional ISAR imaging requires more motion components to be estimated. In this paper we present a sparsity driven algorithm that tackles the problem of three dimensional ISAR auto-focusing based on relative motion estimation.

In order to avoid the receiver saturation, the low-earth-orbit spaceborne MiniSAR system uses the integrated transceiver for data collection. However, this kind of transceiver can be in one state of transmitting or receiving only at any one time, which will cause the periodic loss of collected data. In this paper, an L2,1-norm regularization based sparse SAR imaging method is proposed to process the azimuth periodic block sampling data. Because the ghosting terms caused by the periodic block sampling are considered in the scene recovery, it can effectively suppress the ghosts to achieve high-resolution sparse scene reconstruction.

Maximum unambiguous range in pulsed radars is a function of transmit inter pulse period(T). For high speed and highly maneuvering targets the inter pulse period has to be sufficiently small to extract intelligible information from radar returns for quick threat analysis and possible target engagement. So a high pulse repetition frequency (HPRF) system is required to work with this class of targets. But HPRF systems have ambiguous range problem which requires complex processing schemes for range extraction. And to utilize the unambiguous range rate information for range extraction we require initial position of the target, which mandates additional communication link with other sensors in the network. On the other hand, low PRF (LPRF) systems have unambiguous range information but very high inter pulse period which is detrimental for tracking high speed targets. In this paper we propose interleaved low PRF processing amidst staggered high PRFs to leverage the benefits of both the schemes. We propose fusion of range unfolding algorithm for staggered high PRFs based on Optimized Chinese Remainder Theorem(OCRT) along with compressed sensing(CS) based interleaved low PRF processing for initial range estimation and to provide range reference for correcting estimation errors at periodic intervals. Both the methods run in parallel channels and the output is fused to obtain improved range estimates.

In this paper we extend the successive concave sparsity approximation (SCSA) algorithm to complex numbers in order to make it available for applications benefiting of it e.g. radar applications. SCSA is an attractive reconstruction algorithm for compressive sensing (CS) problems due to its high reconstruction performance (superior to l1 algorithms) and in particular since it does not require any "hard" parameters,unlike all hard thresholding (HT) algorithms, which may be unknown in radar applications. We call this extended version complex successive concave sparsity approximation (CSCSA) and evaluate its performance by use of phase transition plots for random and discrete Fourier transform (DFT) sensing operators and further compare it with the two well known algorithms normalized iterative hard thresholding (NIHT) and fast iterative shrinkage-thresholding algorithm (FISTA), where we especially show how the reconstruction performance of NIHT declines in case of wrongly assumed parameters.

PL612, one of the three Polish LOFAR stations is fully operational in the International LOFAR Telescope (ILT) since beginning of 2016. In second half of 2016 we have also started a pulsar observational projects in the local mode using the bałdy LOFAR station. In this paper we shortly describe a new project which focuses on the simultaneous observation of pulsars and the TEC parameter towards them in the sky.

We present a few examples of the type III solar radio bursts observed on 25th August 2017 with LOFAR (LOw-Frequency Array) station in Baldy, Poland. This station recorded the solar dynamic spectra in the frequency range from 10 MHz up to 250 MHz. The time and frequency resolution of the spectra were 1 s and 0.39 MHz respectively. The preliminary analysis of these radio events indicate that observations with use of the Baldy LOFAR station, in single mode, can give a lot of interesting results.

The development and the current state of the LOFAR-Latvia station is described. The proposed research is presented in the context of both the surrounding infrastructure of Ventspils International Radio Astronomy Centre (VIRAC) and of the established research directions with the focus on the field of solar and heliospheric physics.

In this paper we present the current status of the pulsar observations conduct by Polish LOFAR stations. In particular we show that the single LOFAR station can provide observations that are of sufficient quality to provide useful scientific data. These can help us to better understand some of the phenomena related to the pulsar emission and the influence of the interstellar matter.

The capability of passive radar employing radio telescope as a receiver and digital radio broadcasting (DAB+) as an illuminator of opportunity is analyzed in the paper. The principle of LOFAR radio telescope is presented with deep analyses of using such radio telescope as passive radar for detection of aerial (airplanes) and space (satellite) targets. The theoretical considerations are illustrated by the description of signal processing schema and presentation of measurement results.

In this paper practical results of drone detection and tracking in a DVB-T2 passive radar system are presented. DVB-T2 signal from TV tower was used to detect and measure distance and velocity of a drone. To increase SNR, adaptive filtering and re-modulation of DVB-T2 signal was applied before the detection. Since integration time of the reflected signal is large, a non-trivial fast convolution algorithm was used to reduce the computational expense. Detection was done by CFAR algorithm. Finally, it was shown that in range-doppler matrix peaks from drone's propellers are visible what can be used for its type identification

This paper shows a study about the use of sparse frequency signals for the improvement of passive radar systems capabilities based on DVB-T. The analysis was performed on real signals acquired by IDEPAR, a demonstrator developed at the University of Alcalá. Data has been obtained by upgrading platforms acquisition cards to USRP X310, which have enough bandwidth to acquire groups of DVB-T channels scattered in frequency. A double analysis has been carried out/performed to determine the improvement of detector capacity by comparing the initial version of IDEPAR and the updated one. Firstly, the pedestal estimation of the ambiguity function of the acquired reference signal is presented, which is directly related to the signal-to-noise ratio of the system. Secondly, the Range-Doppler maps obtained after the coherent processing of the signals are analyzed. In this case, the average signal to interference ratio along the trajectory of three targets is calculated. The results show an improvement in capabilities by increasing the useful bandwidth of the acquired signals.

Device-Free Passive Localization (DFPL) is capable of detecting and locating an object without requiring the object to hold any device, nor to participate actively in the localization process. This system is based on wireless sensor networks (WSN) and analyzes the reflections of wireless signals from the object. A method to localize an object based on time-delays in the channel impulse response (CIR) and an elliptical model is presented. Radar imaging is used to generate a heatmap of the environment. With the help of IEEE 802.15.4 ranging modules the algorithm is evaluated with measurements in a radio-frequency anechoic chamber.

This paper presents two calibration procedures for ultra-wideband SDR Zero-IF receiver operating in 1 GHz to 6 GHz frequency range. The IQ-imbalance compensation procedure trained with an additional testing monochromatic signal and based on complex FIR filter allows Image Rejection Ratio (IRR) better than -65 dBFS over 600 MHz bandwidth. For DC-offset minimization a hybrid method based on AC coupling with very low cut-off frequency and DAC-controlled hardware balancer of ADC inputs was developed. The level of the DC component in the output spectrum after calibration is close to -70 dBFS. Stability of both compensation methods over time has been examined.

In this paper, an incremental modeling technique is proposed as an efficient substitute for the costly approximation methods used in behavioral modeling of active microwave devices. In this technique, cheap interpolation models are being extracted on a subset of training dataset. The rest of the dataset guides the algorithm which samples to include in the interpolation. The model is built by subsequently adding the samples that minimize the information loss given by Akaike information criterion. This criterion allows to choose a good compromise between the model accuracy and complexity. The results of the modeling of the complex wave quantities of GaN HEMT show that incremental modeling yields comparable and sometimes lower errors to the models interpolating with even order-of-magnitude more samples. The results also show that the incremental modeling greatly reduces overfitting.

The use of the calibration tower to test a monopulse tracking system is expensive and requires the antenna downtime. Alternative ways to test in-lab the tracking system are highly-desirable. This work proposes a simple yet effective structure achieving this objective through the controlled excitation of high-order modes in a circular waveguide that mimic those generated by the signal received from the calibration tower. The theoretical fundamentals are discussed and the design of the waveguide mode exciter at K band is reported, along with results showing its validation.

Analog-Multiplexers (AMUXs) are attractive architectures to increase electro-optical transmitters' analog bandwidth through the time interleaving of several high-speed digital-to-analog converters' outputs, to enable the transmission of high order electrical modulation formats (PAM-4, PAM-8) for ultra high capacity (>1Tb/s/channel) optical communications. In this paper, we present the design, fabrication and measurement of AMUX circuit realized in the III-V Lab in-house InP DHBT technology. The design challenges and necessary tradeoffs are discussed. Measurements of PAM-4 AMUX output signals up to 100 GBd with an over 1-V differential output swing are presented.

In the paper, microwave amplitude and phase noise mutual conversion is studied for optoelectronic oscillator (OEO) with all-optical gain. It is shown that microwave amplitude and phase noise mutual conversion in the OEO loop is possible due to its non-linear time-variant dynamics, especially in the state near the oscillation threshold. The correlation between amplitude and phase noise effects the OEO output noise power spectrum density. It is shown experimentally that decreasing of the amplitude noise injected in the OEO loop allows to decrease the phase noise of the output signal. Methods for reducing the amplitude and phase noise mutual conversion and consequential phase noise performance increasing are proposed.

Rapid development of terahertz technologies causes constant search for new possibilities of making optical elements, needed for proper beam shaping. Large optical elements are often used in THz setups to collect as much power as possible. Unfortunately, traditional refractive optical lenses significantly absorb already weak signal. This is the reason for searching for new solutions in the form of diffractive optical elements (DOEs). For higher terahertz frequencies however, it is challenging to find an appropriate material as well as uncomplicated manufacturing methods. In this article, we present a higher-order kinoform (HOK) made of paraffin, cast from 3D-printed mold, efficiently working for 0.6 THz.

Every new optical element require proper characterization. The same situation is with diffractive elements working in terahertz range. In this paper we present the procedures applied for measurements of an off-axis diffractive lenses. Problems and solutions for noncollinear experimental setup configuration are discussed. Results acquired by using three semiconductor detectors with different apertures are compared.

This paper presents the design of a D-band frequency quadrupler (FQ) based on two cascaded frequency doublers. Each doubler relies on the bootstrapped Gilbert cell (GC) mixers. The FQ is developed with a standard 130-nm SiGe BiCMOS process. It consists of fully integrated input and output baluns, frequency doublers, and matching networks. The design of the FQ was optimized via single-ended matching networks to reduce the chip area and increase bandwidth. The results based on the EM-simulation of FQ with the assistance of the hicum model for the transistor, demonstrate a peak conversion gain and output power of 25 dB and 5 dBm, respectively at 130 GHz. The FQ shows a 3-dB bandwidth higher than 84 GHz with an nth harmonic rejection of at least 16 dBc. The FQ can be exploited in various systems design for different D-band applications. The future work includes measurement of the FQ.

In this work, the authors focused on assessing the reliability of the dense wireless network that draws inspiration from the human nervous system. The concept of such a network was created using the action of a glial cell, i.e. microglia, which is involved in the damaged nerve connections repair process. To assess reliability, the authors used the percolation theory, in particular the percolation threshold. This approach makes the results of simulations independent of the specific network topology. In the simulations carried out, the reliability level of the analyzed systems were also appointed.

The problem of waveforms constructing for mobile ad hoc networks with cognitive radio (MANET-CR) is discussed. This is one of the main questions limiting widely use this very attractive technique, that not need deployment of expensive communication infrastructure. The paper presents the structure of CR nodes with complex management procedures, using advanced Dynamic Spectrum Management together with the concept of policy-based radio. Here, the basic policy is to avoid interference generated by other users or interfering devices. The experiments were performed in a real environment, using the elaborated testbed. The results show that the use of sensing and cognitive management mechanisms enables more efficient use of the spectrum while maintaining reasonable overhead values related to the management procedures

This paper presents an efficient method of cooperative spectrum sensing for mobile radio networks with the hierarchical management structure. The network is divided into clusters controlled by cluster heads. All cluster members perform spectrum sensing using energy detectors. Sensing results are then transmitted to fusion centers in cluster heads, where they are combined using evidence theory based on Dempster-Shafer theory. The achieved simulation results show that the proposed method outperforms commonly used rules and gives a high probability of proper signal detection and low probability of false alarms.

This paper presents advantages of the machine learning used for estimation of specific radio channel usefulness, necessary for dynamic spectrum access. This method enables more efficient use of spectral resources, that are temporarily not used by licensed users. It indicates which channels are the most useful, i.e. give the highest probability of successful transmission and avoidance of interferences. Profile of Q-learning algorithm operation may be controlled by adaptation of the learning rate and greedy parameter

A comparison of techniques for software calibration of lumped ports is presented in this paper. Three calibration techniques are investigated: double delay method, short-open calibration, and analytic evaluation of port parasitic inductance. All methods were applied to the same microstrip device and the efficiency of each calibration technique is discussed in the results section.

We investigate the concept of multitone X-parameters for characterizing the behavior of an off-the-shelf power amplifier under wideband excitation similar to real-life telecommunication signals. To achieve this, we created a set of random phase multitone excitations and identified large- and small-signal terms for each wideband signal. For simplification, we ignored terms describing mixing and harmonic-related products. We show how the terms identified are affected by input signal conditions by presenting and discussing results for two exemplary multitone realizations. For this investigation, we kept the power amplifier's load conditions constant.

This paper presents a wireless planar microwave sensor operating at industrial scientific and medical (ISM) frequency for the detection of dielectric materials. The microwave sensor consists of a reader (ground defected microstrip coupled line) and a passive tag where a complementary split-ring resonator (CSRR) made on the commercially available copper-foil. The CSRR is a peel-off type tag that is excited using the near field of microstrip coupled transmission line. The near field coupling, the low-cost passive tag design, and the high sensitivity (~250 MHz change per unit change in dielectric constant) make the proposed sensor wireless, cost-effective, and reliable.

We describe a new system for broadband characterization of mid-infrared (MIR) photodetectors, manufactured by the VIGO System and encapsulated in TO-8 can. The system comprises a high repetition rate pulsed laser source, stimulating a detector in a special test fixture that is connected to ports of a vector network analyzer (VNA) with a pair of cables. After calibrating the VNA at the cable ends using the thru-reflect match (TRM) method supplemented with power and phase calibration, it operates in mode of nonlinear VNA, i.e. it is capable of measuring magnitude and phase spectra of harmonic signals both corrected for effects of systematic errors. In order to recover the differential signal at the detector reference plane on the can header, we utilize the transfer matrix of the test fixture, which counts 16 nonzero entries due to signal crosstalk in the fixture. This matrix is determined with another calibration procedure, based on measuring special built-in-house standards, mounted inside TO-8 housing. With the matrix determined, we transfer the measured spectra to the TO-8 reference plane and then convert them with IFFT to the time-domain. This approach enables recovering sub-nanosecond differential pulses of amplitudes below 1 mV and speed up performance evaluation of MIR detectors tested.

The analysis of the possibilities for the fully digital microwave frequency discriminator (MFD) realization has been presented in the paper. In classic hardware solutions MFD consists microwave phase discriminator and microwave detectors, realized as microwave circuit. Authors propose a solution completely deprived of the analog microwave circuit, based on the fast A/C converter. Mathematical operations carried out in the microwave circuit are digitally executed, on digital signal samples. The receiver was implemented as the 3-channel MFD, this one gives unambiguous determination of the instantaneous frequency value and high accuracy in the 700 - 3000 MHz band. For the physical implementation fast digitizer with 12,5 GS/s speed was used and the overall digital processing in the programming LabVIEW environment has been realized. Proposed solution corresponds to the parameters and functionality of the MFD systems in the classic version. Laboratory tests with real RF signals have been made. The measurement accuracy not worse than 10 MHz were obtained, with the most measurements being no worse than 3 MHz.

The paper summarizes experience with the development of high-frequency electronic components which are manufactured on a three-dimensional knitted material instead of a conventional microwave substrate. Attention is turned to specific aspects of the design, manufacturing and integration of components to applications. Technological problems, which have not been solved yet, are discussed.

The paper summarizes the experience with the development, production and optimization of 3D fabrics, specifically 3D weft knitted fabrics, planned for the integration of electronic components. Attention is focused on the presentation of 3D fabrics general properties which are given by their structure, used materials and finishing. The technological possibilities of preparation of this type of fabrics are summarized and their limits are described in detail and possible application areas are outlined. The possibilities of surface treatment from coating, lamination to printing or embossing are presented in order to optimize the fabric surface for a given application.

The paper deals with the relative permittivity measurement of the selected types of 3D-knitted fabrics by the two-line method combined with the matrix-pencil method and by the transmission/reflection method. The measured relative permittivity of the fabrics is in the range from 1.17 to 1.23. Further, the fabrics exhibit slight anisotropic behavior. The obtained results can be used for the design of the microwave devices where the 3D knitted fabrics play the role of the substrate.

The paper summarizes experience with electromagnetic interference (EMI) noise background measurements on the board of aircraft EVEKTOR EV-55 in the development phase. Measurements were aimed to select optimum frequency bands for the operation of on-board textile-integrated electronics. The EMI background was measured in four places situated along the center of the aircraft body. Measurement scenarios comprised several aircraft operation conditions like the running engine, power only on batteries, transmission on the radio etc. The appropriate ISM communication channel at 5.8 GHz was selected due to the lower noise interference and acceptable dimensions of textile-integrated microwave components.

In the paper, frequency limitations of textile integrated antennas and filters based on textile integrated waveguides are discussed. The antennas and filters are manufactured from a three-dimensional knitted material. Conductive parts are manufactured from silver-coated conductive threads and by a screen-printing technology. Textile antennas and filters presented in an open literature are reviewed and compared. The technology, manufacturing process and limitations are analyzed and discussed.

The purpose of this work was to create a wireless Internet-of-Things (IoT) communication module for a device for measuring soil parameters in a field environment. The module uses the Low Power Wide Area Network (LPWAN) technology to exchange data with an external database. This paper contains information about design assumptions, research on the existing long-range communication technology solutions and description of the design process.

This paper presents a method for determining a six-port reflectometer's response to a matched load with the use of partially known calibration loads. It utilizes nine calibration loads which can be of unknown magnitude and phase, however, three of them must exhibit magnitudes possibly close to each other with a reasonable phase separation. The algorithm was tested with the use of an exemplary broadband six-port reflectometer operating over the frequency range from 2.5 GHz to 3.5 GHz. The power values obtained using the proposed method are very close to those directly measured by the six-port reflectometer with a broadband matched load from precision calibration kit connected as DUT.

In this paper authors presents very important problem of estimation capacitance structures used in MEMS sensors. The importance comes from fact that during operation, inertial sensors which are build of solid materials deform because of external forces acting on them. Therefore typical capacitor consists of some electrodes changes its value because electrode changes its orientation. Here authors use analytical and FEM results to compare capacitance results and impact on accuracy of measurement.

In the paper authors take into considerations results of analysis both MEMS accelerometers and gyroscopes under performance that can be changed by some geometry details modifications. Authors considers different types of shapes of springs to show, how they influence on total device operations.

The instantaneous frequency measurement (IFM) devices are very useful for very fast measurement of current frequency value of microwave signals even if their duration is extremely short. A fast measurement of temporary value of frequency is based on evaluation of a phase difference of signals propagating through the microwave transmission lines having unequal but known lengths. This phase difference is provided by so-called proportional phase shift forming network (PPhSFN), and the phase difference measurement is performed by the microwave phase discriminator (MPhD). The main segment of MPhD is a microwave six-port made of several microwave splitters and combiners. The paper presents integrated version of microwave correlator containing PPhFS and six-port on a single printed circuit board (PCB). The developed device was designed to work over WiFi frequency range. The frequency bandwidth of the made correlator reaches nearly one octave.

The paper presents the attempt of finding optimal solutions regarding the emission type, basic emission parameters and channel capacity for the trans-ice longwave communication channel, as deployed in June 2019 during the first edition of the IGLUNA programme - a simulated lunar habitat in the Klein Matterhorn glacier in Switzerland. The experimental system is compared to lowland high-power longwave systems, the optimal emission type for different conditions (modulation index, demanded presence of carrier) is presented and the maximum possible channel capacity in relation to the achieved signal readability is calculated.

High power electromagnetic pulse weapon (EMP) is a new kind of weapon which can directly transmit high power microwave to damage the target electronic equipment. This paper introduces the damage mechanism of high power microwave, describes the working principle of the marine navigation radar and the front-end structure of receiver. The damage ability of high power microwave to marine navigation radar receiver is calculated and analyzed, at the same time, the damage range of high power microwave to marine navigation radar is given under the different states of power center and power edge.

3D printing offers a very innovative opportunity for creating cheap or special rf-components like waveguides, couplers or antennas. However, these components require electrical conductive materials to be built of. Therefore, selective laser melting of metal powder is also an attractive production technology. In this paper, horn antennas and a directional coupler at 24 GHz are shown and their production technologies are compared. By presenting a K-band branchline coupler it is shown that selective laser melting has some advantages over 3D printing.

The proposed radar system is characterized by cheap equipment (omnidirectional microphones, a computer for signal processing, and peripherals) and by the special algorithm of signal processing, which has been developed and tested during full-scale experiments with real targets: aircrafts and UAVs. A key feature of the developed algorithm is a fast method of estimation of wideband ambiguity function. In addition, the algorithm provides visualization of the target location process using the projection of the ambiguity function onto a coordinate plane. The developed radar system is proposed to use for aircraft noise management in the vicinity of an airport and for localization of small-sized flying vehicles. The results of the experiments are presented in the paper

the Weightless(-P) is a narrowband communication system designed for the Internet of Things, along with some other counterparts such as Lora and SigFox. As a system dedicated specifically for long-range operations, it possesses a considerable processing gain for the energetic link budget improvement and a remarkable immunity to multipath and interference. The paper describes outcomes of measurement campaign during which the Weightless(-P) performance was tested against variable interference, generated in an anechoic chamber. Results allow to quantitatively appraise the system behavior under these harsh conditions with respect to the modulation and the resultant bandwidth. The outcomes allowed to propose recommendations regarding the use of particular system settings to optimally fit environmental conditions. Finally, the paper provides an analysis in which CNIR is converted to the Interference Margin and its value is checked against an intentional jammer approaching the base station to verify how different Weightless operational modes respond to electromagnetic jamming.

This paper deals with a model-order reduction method, applied to speed-up the simulations of MIMO antenna arrays, performed by means of finite element method. The obtained results of the numerical tests show that the described technique is reliable and considerably increases the efficiency of the standard finite element method.

Radar technology in the mm-wave frequency band is a promising approach for the detection of birds and bats at wind turbine installations in order to reduce fatalities either by direct collision of the animals with the rotor blades or through barotrauma. In this paper we present an FMCW radar system with 1 Tx and 9 Rx operating in the Ka-band from 33.4 GHz to 36.0 GHz. The radar system is installed at the tower of a 2MW wind energy plant about 95m above ground. The data acquisition is described in this paper including the real-time processing pipeline, followed by exemplary bird detections. Also the detection of drones, serving here as an artificial flying object with a defined flight path, will be presented and discussed. Validation is performed by concurrent camera recordings.

The specially calculated reflecting surfaces with Stealth invisible quality designed for to avoid vertical ones for ra-dar beam and to reflect beam "to the milk". Stealth coatings with the full absorption of the micro-wave radar radiation on his surfaces are blackbody and reasonable to consider it as the matched loading with the corresponding physical outside temperature. A lot of news and minding has place about the Stealth application especially in the contest of an airplanes. Possi-bility to avoid the disclosing of an airplane on the big dis-tances is main advantage of this Stealth "addition" against of the radars. But in much cases for the microwave radi-ometers this Stealth coating can be good for the real deter-mination by the passive devices because their job based on the measuring the radio-brightness contrast between Stealth objects and the background of the environment/s (sky is cold, Earth is warm). The aim of this short report - to present some under-standing about to use radiometer about Stealth objects

In this paper, influence of dielectric overlay permittivity on miniaturized ESPAR antenna parameters is presented. ESPAR antenna is a low-cost and energy-efficient way to implement beam steering capability to a node and improve network performance. The antenna size reduction is obtained by embedding its active and passive elements in ABS based materials of relative permittivity equal to 4, 5.5 and 7.5 in order to achieve network node compact size. Simulation results of three optimized for particular dielectric constant designs are presented and tradeoff between dimensions reduction and performance is discussed. Selected materials and antenna design are dedicated to be fabricated in 3D print technology, so can be easily prototyped.

Microwave propagation in the atmosphere is affected by air temperature, humidity, attitude, and other factors, there are many related researches on the above influencing factors, but relatively few researches are attached on the microwave propagation characteristics under the condition of sea salt mist. It is of great significance to clarify the law of microwave propagation attenuation under the condition of salt mist for the microwave applications such as maritime communication and radar detection. Firstly, the parameters of the salt mist environment are analyzed and modeled in this paper, and it is driven that the relationship between the concentration of the salt mist and the dielectric constant of the atmosphere. Then, based on the FDTD numerical analysis, the microwave propagation law under different concentration of the salt mist is calculated and compared with the theoretical analysis results.

This paper describes an experimental setup that was built to imitate the performance of the new microwave personnel screening system, in which synthetic aperture is formed due to relative motion of the subject in the vicinity of a sparse antenna array. The RGB-D sensor captures a color image and a depth map of a still scene with a mannequin, while the compact network analyzer, which is moved by a two-dimensional scanner, acquires the samples of the radar signal reflected from the same scene. The mannequin is moved by the third linear drive module to another position, creating the next still scene to be scanned and captured similarly during a single experiment. The collected data is stored for the following joint processing. Preliminary radar images of concealed objects on mannequin are obtained and demonstrated. The use cases of the experimental setup are described toward designing a sparse electronically switched antenna array: finding the required number of the channels, choosing proper frequency band and bandwidth, antenna type, and others.

The paper presents an algorithm for positioning of a handheld ground-penetrating radar antenna. The algorithm has been elaborated for processing range measurements in a currently developed positioning system based on ultrawideband radio modules. Such a system is planned to be used as a support for a handheld ground-penetrating radar as continuous and accurate positioning of its antenna can facilitate creation of high-quality subsurface images. The paper contains a short description of the developed system and focuses on its Kalman filter used for positioning. Here, we consider using a novel dynamics model, based on a pendulum motion model, which provides a more adequate description of the antenna's dynamics than abstract position-velocity or position-velocity-acceleration models, commonly used in navigation systems. Chosen simulation results which support this claim are presented.

The paper presents an implementation of analog front-end designed for use in an X-band Frequency Modulated Continuous Wave (FMCW) radar system. Fine range resolution is achieved because of using more than 1 GHz of bandwidth, which is achieved through application of frequency multipliers. The system has been tested in laboratory as well as in a real environment using a USRP (Universal Software Radio Peripheral) device for both, waveform generation and beat signal digitization.

Background subtraction is usual step in impulse radar applications. It is used to not only remove clutter - reflections of all the stationary, mostly irrelevant objects, but also crosstalk. Various techniques are used for clutter/crosstalk removal. These are briefly over-viewed. Focus of this paper, however, is on proposed method of adaptive background subtraction, which is statistical real time method based on developments of entirely different field (Computer Vision)

This paper explores the possibility of using a synthetic aperture radar to detect surface defects of rails and measure parameters of rail junctions. Experimental data were obtained with a setup consisting of a two-coordinate electromechanical scanner and a radar emitting continuous stepped-frequency signal in the range of 22.2 - 26.2 GHz. As an object of study, fragments of narrow-gauge rails were used, in which surface defects of various sizes and depths were created. A phase method for radar signal processing based on the backward propagation of its wavefront was developed, with which radar images of rails with defects were obtained. Experimental studies have shown that the developed rail surface imaging method allows detecting the presence and measuring characteristics of cracks on the tread, cleavages of the railhead, the width of the joint gap and the magnitude of the vertical step at the rails joint. High accuracy and sensitivity of the radar method, confirmed with the contact measurements matching, allow using it for fast noncontact diagnostics of the rails condition.

For polarimetric synthetic aperture radar (PolSAR) images, building extraction has been a challenging topic for long time in applications of land-use and land-cover analysis. Due to similar structures of buildings and such vegetation as forest, they often exhibit similar PolSAR scattering characteristics that are often difficult to distinguishing. Recently, deep Convolutional Neural Network (CNN) has been widely investigated for image processing with many promising results. This paper proposes a method that combines polarimetric features with the CNN network to realize the comprehensive utilization of polarimetric and contextual information of PolSAR data for the extraction of building areas in PolSAR images. Comparison experiments on both ESAR and EMISAR L-band PolSAR datasets show that the proposed method can generate better results for building extraction.

Recently, Interest on circular SAR (CSAR) has been increased in researchers. The sub-aperture division and trajectory reconstruction of ground moving target are important parts of the CSAR research. Firstly, the CSAR sub-aperture is fitted by a second-order curve, which achieves better focusing quality than the traditional fitting method. Next, parameter estimation accuracy is improved of each CSAR sub-aperture. Finally, the trajectory of ground moving target is reconstructed. Simulated data are used to prove the effectiveness and correctness of the proposed method.

This paper introduce an approach for detecting bridges when the difference in radar echo energy is not obvious. It consists of two steps: extracting targets with high anisotropy and detecting bridge. Firstly, by image segmentation based on the feature of multi-aperture polarimetric entropy, we get targets with high certainty. And then we utilize edge detection to extract straight line segmentations. Finally, the parallel straight line segmentations which meet the bridges' geometric properties are selected as bridges. The proposed approach has been test with polarimetric CSAR data, and the experimental results show that our method can detect bridges effectively.

A novel global range alignment technique for inverse synthetic aperture radar (ISAR) imaging is presented in this paper. Instead of requiring the parametric model for the relative offset amongst the range profiles, the alignment is investigated from the viewpoint of optimization, where the minimization of the entropy of the sum range profile (SRP) is employed as the optimization criterion. The precise range alignment within a range cell can be achieved by implementing the proposed algorithm. With respect to the existing global method, the proposed one does not require any interpolation operation and multidimensional search operation. Experimental results based on real measured data of maritime non-cooperative target validate the effectiveness and the efficiency of the proposed algorithm.

In this paper, a general iterative thresholding algorithm (ITA) for solving Lq-norm regularization problem is proposed to achieve the synthetic aperture radar (SAR) image feature enhancement. Compared with the reconstructed images by matched filtering (MF) based method, the proposed method recovered images have lower sidelobes, reduced noise and clutter, which improves the image quality effectively. Experiments basedon Gaofen-3 (GF-3) SAR complex image data are used to validate the proposed method.

A real-time imaging right side-looking synthetic aperture radar (SAR) motion error model is established in this paper, and a center beam motion compensation algorithm based on inertial navigation and phase gradient autofocus (PGA) motion error estimation is adopted. The algorithm compensates the echo envelope and phase separately, and uses the inertial navigation data to straighten the echo envelope with motion error, and then uses the phase gradient autofocus algorithm to estimate and compensate the phase error of the echo. In view of the characteristics of real-time imaging, such as short time, large amount of computation and limited computing resources, the algorithm cancels the steps of range migration correction, projects the motion error vector on the slant plane, and completes envelope correction and phase error estimation. The method has a small amount of calculation and can meet the resolution requirement. The simulation results show that it can obtain high quality SAR images.

Surveillance radars form the first line of defense in border areas. But due to highly uneven terrains, there are pockets of vulnerability for the enemy to move undetected till they are in the blind range of the radar. This class of targets are termed the 'pop up' targets. They pose a serious threat as they can inflict severe damage to life and property. Blind ranges occur by way of design in pulsed radars. To minimize the blind range problem, multistatic radar configuration or dual pulse trans- mission methods were proposed. Multistatic radar configuration is highly hardware intensive and dual pulse transmission could only reduce the blind range, not eliminate it. In this work we propose, elimination of blind range using deep learning based video tracking for mono static surveillance radars. Since radars operate in deploy and forget mode, visual system must also operate in a similar way for added advantage. Deep Learning paved way for automatic target detection and classification. However, a deep learning architecture is inherently not capable of tracking because of frame to frame independence in processing. To overcome this limitation, we use prior information from past detections to establish frame to frame correlation and predict future positions of target using a method inspired from CFAR in a parallel channel for target tracking.

Space-Time Adaptive Processing (STAP) enables detection of a moving object against the background of strong interference by radar. The fundamental principles of the STAP technique for radar signal processing in particular, detecting slow moving objects against interference. are presented in this paper. The parameter (improvement factor), determining the performance of any linear processor was analysed. A disturbance model has been proposed, for which the dependence determining the performance of any STAP processor has been derived. The results of simulation of the optimal processor performance against the suboptimal processor for three different values of noise to interference ratios in reference channels were presented in the paper.

This paper concerns the problem of maximum likelihood (ML) estimation in the case of impulsive observations modeled by heavy-tailed α-stable distributions. To describe analytically the cost function in ML estimation criterion the Fox function representation of α-stable distributions is used.

The paper presents the results of experimental studies on evaluation of employing digital predistortion based on simple feedforward neural network for linearization of microwave power amplifiers. The influence of the number of neurons in the hidden layer, the number of delayed input samples at the input of neural network, as well as the number of samples taken for learning a neural network were studied and discussed in the paper. The main goal of this work was to establish the minimal configuration of the neural network which can be used for linearization of power amplifiers excited by wideband and high PAPR signals, e.g. LTE. The results obtained for neural networks were compared with the results obtained for the conventional predistortion method based on memory polynomial.

We report anomalous behavior of the response in GaN/AlGaN fin-shaped field effect transistors at sub-THz frequency range. For transistors with the gate length much bigger than the width of the channel an unusual growth of the absolute value of the response signal was observed with applying positive gate voltage.

In this paper, we show experimental evidence of the applicability of a field-effect transistor-based THz detector (TeraFET) for the simultaneous hyperspectral raster scanning imaging. For this work, we have used a dual frequency comb setup extended to THz frequencies, as well as a TeraFET detector adopted for a higher frequency readout circuit. Such a spectroscopic imaging system can acquire simultaneously many frequency lines with an outstanding frequency accuracy and adjustable frequency resolution even at very low THz source power. The dual frequency comb THz system is also capable of narrow linewidth, which makes spectroscopy measurements with high resolution more feasible. The TeraFET detector has optical NEP below 19 pW/Hz^0.5 at 296 GHz. Additionally, the detector was supplemented with a low-noise amplifier of 40.8 dB gain and 200 kHz 3-dB bandwidth

In this paper we report on terahertz detection by field-effect transistors in 65-nm CMOS technology with on-chip integrated patch antennas. In conjunction with continuous wave photomixer source, detectors demonstrate > 40 dB signal-to-noise ratio and minimal NEP of 12~pW/√Hz @1 kHz of chopping at the resonant frequency of 620 GHz. This NEP value by few pW/√Hz lower than best reported values for this category of detectors which gradually approaches the state-of-the-art characteristics of THz bolometers.

The comparison of two full-wave models of photoconductive terahertz antenna is performed. One model solves simple approximation of drift-diffusion equations another uses Monte Carlo simulation for estimation of the electrical current in the active region of antenna. Simulation results revealed that the simple model can be useful in the cases when the duration of photoexcitation is relatively long (FWHM >= 250 fs). In a case of shorter laser pulses and usual electron recombination times in compensated gallium arsenide, transient dynamics of electron drift velocity at sub-picosecond time scales makes significant impact to the growth speed of photocurrent. For this reason, the simple model leads to the overestimation of electric field amplitude in the high-frequency range. Full-wave simulation shows good agreement with experimental results when detectors' response is included in calculation. Calculated results were confirmed experimentally what increases the reliability of the full-wave model presented in the paper.

Photon detectors operating in infrared and terahertz spectral ranges require cryogenic cooling to achieve useful performance. The need for cooling is a major limitation of IR photon detectors what prevents more widespread use of IR technology. At present, uncooled thermal detector focal plane arrays are successfully used in staring thermal imagers. However, the performance of thermal detectors is modest, they suffer from slow response and they are not very useful in applications requiring multispectral detection. Initial efforts to develop high operating temperature (HOT) photodetectors were concentrated on HgCdTe photoconductors and photoelectromagnetic detectors. More recently, technological efforts have been directed on advanced heterojunction photovoltaic HgCdTe detectors. In the paper, a number of concepts to improve performance of photon detectors operating at room temperature are presented. Several types of detector materials are considered: HgCdTe, type-II AIIIBV superlattices, two-dimensional materials and colloidal quantum dots. At present stage of HgCdTe technology, the Rule 07 metric is not a good approach for prediction of HgCdTe detector and system performance and as a reference benchmark for alternative technologies. It is shown that uncooled depletion-limited HgCdTe photovoltaic detector can achieve background limited detectivity in long wavelength infrared spectral range at room temperature. In this context are considered alternative technologies. It is shown that it will be rather difficult to rival 2D material and colloidal quantum dot photodetectors with HgCdTe photodiodes. The above estimations provide further encouragement for achieving low-cost and high performance MWIR and LWIR HgCdTe focal plane arrays operated in HOT conditions.

Target initiation is one of the most complex parts of the Multi-Static Primary Surveillance Radar (MSPSR) tracking system. Many approaches to solving this problem exist and they mainly focus on decreasing the computational complexity by reducing the number of bistatic tracks in each hypothesis. Another approaches using target movement model assumption or extended set of measurements such as Angle of Arrival (AoA) were also proposed. However, such information may not be available in every system. In this paper, we propose target initiation/deghosting algorithm based on Expectation Maximization (EM) algorithm which focuses on likelihood maximization over the whole set of bistatic measurements. The algorithm description is presented with the detailed analysis of available options for each step. We also discuss advantages of our approach and present some results using simulated data.

Commercial ADS-B data providers deliver massive amounts of continuous data for aircraft traffic worldwide. They are therefore an ideal source for statistical analysis of traffic flows and anomaly detection. By clearly identifying the aircraft using the ICAO code, unique trajectories are obtained worldwide that allow the pattern-of-life of each aircraft to be understood. Furthermore, with modern machine learning technologies and parallel processing frameworks such as Spark, heat maps can be generated and areas of interest, e.g. airports, can be found, which in turn are a starting point for further analysis. The investigation of the change over time of these statistics is part of this paper, as well as the detection of anomalies in the statistics with the usage of an autoencoder deep learning network.

In this paper, a linear least squares (LLS) estimator to solve the range-based positioning problem is investigated. We show that the LLS estimation can use a subset of or the whole available information. The former yields many single set (SS) solutions and the later yields the full set (FS) solution. We also show that the FS solution can refine the SS solutions. An experiment with phase of arrival (PoA) measurements demonstrates that the FS and SS solutions have different accuracies. The FS solution corresponds to the average of the SS solutions. The FS solution was utilized to reduce the SS positioning errors by about 8-28%.

Random Finite Sets become a prominent method for the definition of Bayesian multi target tracking. Often these tracking methods are derived by probability generating functional which requires a broader mathematical background. This paper considers a concrete implementation of a rather advanced type of Bayesian Multi Target Tracking - the so-called Gaussian Poisson Multi Bernoulli Mixture Filter. The aim is to introduce this tracking technique, its implementation, specifics and possible applications.

Modern surveillance networks are able to provide trajectories of all kinds of vessels and aircraft worldwide or at least within extended environments. Best known are Automatic Dependent Surveillance - Broadcast (ADS-B) and (Satellite-) Automatic Identification System (AIS) used in air and maritime surveillance. Both of them are cooperative systems. Besides these systems, sensor networks based on ground installations or mounted on airborne and space-based platforms deliver object trajectories independent of any cooperation. Examples include GMTI radar-based systems operating on UAV platforms or imaging systems based on high altitude pseudo satellites (HAPS) and satellites. These surveillance systems enable the extraction of mid- and long-term trajectories of any kind of objects. The real challenge will be to place the trajectories into the right context and to generate situational awareness and estimate the intents of the tracked objects. Activity-based intelligence and the determination of patterns of life are a significant challenge for new systems. In this paper we present use cases addressing i) clustering techniques to identify areas of interest and patterns of life, ii) supervised machine learning for ship type and activity classification, and iii) the generation of spatio-temporal thematic heat-maps to assist routing and mission planning. Finally, these new data analytic techniques have to be integrated in existing near real time surveillance systems. This requires specific system architectures as well as a completely new software and hardware landscape. In summary, trajectory-based data analytics, machine learning and risk assessment is embedded on local or global clouds and uses dedicated mechanisms for distributed and parallel processing.

In some applications such as radio transmitters with loop antennas, h.f. drivers for RFID transmitting coils, wireless h.f. power supplies for biomedical implants and endoscope capsules etc. resonant power amplifiers operate with high-reactance and low-resistance load. The paper analyses an off-nominal Class E ZVS amplifier to identify conditions for its high-efficiency operation with low-resistance load. Power loss of the transistor switch in Class E amplifiers with normalized transistor turn-on time D= 0.5 operating in nominal and off-nominal conditions are compared. Analytical closed-form estimations for power losses in the transistor switch in the off-nominal amplifier are given. Theoretical results experimentally validated have demonstrated that by designing the off-nominal Class E amplifier for a high enough dc supply voltage the power losses in the transistor switch can be significantly reduced. This makes the circuit useful in those applications that require the amplifier to operate with high output current and/or low-resistance load. A laboratory model of the off-nominal amplifier was designed and built to operate at the frequency 140 kHz with output power 50 W, dc supply voltage 24 V, load resistance 2Ohm and D= 0.5. Its measured efficiency was 96 %.

Practical realization of gain-switched Dy3+-doped ZBLAN fiber laser operating at 2.94 µm is reported. The laser is pumped by a 1.1 µm Q-switched ytterbium (III) fiber laser, which was constructed in-house. The ZBLAN fiber laser generates a stable pulse train with repetition rates spanning the range from 25 to 100 kHz. At the repetition rate of 50 kHz, the pulse width is 183 ns while energy and peak power are 0.76 µJ and 4 W, respectively.

In the paper a ballistocardiographic sensor for remote monitoring of activity and vital parameters is presented. The sensor is mainly intended for use in monitoring systems supporting care of elderly persons. It allows to detect occupancy of the piece of furniture, to which it is attached and for estimation of basic vital parameters (heart rate and respiration rate) of the monitored person. The presented device includes three inertial sensors: two accelerometers of different parameters and price and one reference BCG module. The device sends the measurement results to the external server over WiFi. The vital parameters are estimated based on the Continous Wavelet Transform of the registered acceleration signals. The occupancy of the piece of furniture is detected through analysis of current standard deviation of the measured acceleration.

In high-efficiency Class E amplifiers matching circuits are commonly used to transform usually constant load resistance to nominal or off-nominal resistance of the amplifier to ensure its ZVS operation. In some applications such as: wireless power transfer systems, plasma generators, dc-dc power converters as well as in some transmitters Class E amplifiers operate with load resistance or impedance varied in a wide range. This requires that the matching circuit transform the whole range of load resistance into the range of nominal and off-nominal resistance of the amplifier. The paper presents theoretical results for Class E ZVS amplifier with basic parallel π1a and π2a matching circuits loaded with variable resistance. Conditions for ZVS operation of the amplifier with transistor duty cycle D=0.5 and the matching circuits loaded with any load resistance are discussed. Analytical expressions setting the boundaries for ZVS operation of the Class E amplifier with the analyzed matching circuits are given as well. Examples of normalized characteristics of output voltage and output power vs. load resistance for the amplifier are also presented. A design example for the Class E amplifier with π1a matching circuit able to operate with any load resistance is described and verified by simulation with LTSpice.

The article analyses the possibility for surveillance airplanes by using solar radio emission in a forward scatter radar system. It's estimated as the magnitude of SNR at the input of the signal detector calculated depending on the size of airplanes, the way of the airplanes moving relative to the baseline (perpendicularly or parallel) for various values of the solar radio emission. The time of the contact of airplanes with the receiver beam influences on the duration of the signal received from airplanes. Changes in the angular width of the FS zone and in values of the aircraft FS RCS depending on the frequency values of the solar radio emission are also taken account in the calculation of SNR.

Recently proposed methods for generation of entangled (quantum correlated) signals directly in microwave frequency range give more chances for design of QR for long- range applications. In such applications, the range resolution capability is of a great importance. Using analogy of signal generation and processing in Noise Radar and Quantum Radar we describe a novel concept for Stepped-Frequency QR (SF- QR) design which enables preserving quantum properties of probing signals and provide range resolution capability in SF- QR.

Ground Noise SAR exploits either special antenna with pattern synthesis or Tx/Rx antenna motion along a rail path. In both cases, the azimuth resolution is limited by the available/achievable length of Tx/Rx physical antenna motion. However, in many applications it may be not sufficient to provide the required azimuth resolution. At the same time, a sub-meter range resolution is readily achievable with nowadays fast ADCs and wideband sources of random signals. We consider a special operational mode for enhancement of the azimuth resolution via implementing of alternation of SAR and interferometric modes to enhance azimuth resolution (when a target was detected with a high range resolution) via coherent processing of the data obtained from different Rx units of bistatic Ground Noise SAR

Waveform design and optimization algorithms generally assume a zero-Doppler ideal case to reach an optimum or satisfactory solution in terms of the matched filter output. Therefore, its performance is usually characterized only in terms of the resultant waveforms autocorrelation function, neglecting the practical situation in which the received signal is modulated by the target's Doppler shift. Within this context, this work investigates the Doppler mismatch effects in the Integrated Sidelobe Level (ISL) performance of previously designed/optimized noise waveforms. The analysis has shown that, despite much better results for steady targets, the increasing Doppler mismatch reduces the ISL performance of optimized waveforms, until similar levels achieved when no optimization is performed. To address that, a subpulse Doppler processing approach is also considered, and the results have shown that, besides increasing the Doppler tolerance, it has also increased the optimized waveform robustness to the Doppler mismatch, reducing the resultant ISL loss and thus extending its applicability.

Given the nature of current evolving threats, border security has become of paramount importance both in civilian and military application. In particular, both air and maritime borders are threatened by unlawful activities which employ new technologies and require the use of more effective surveillance sensors. Beside facing both civilian and military issues, allowing for all weather/all day operations, new solutions for border security must deal with the fact that smugglers and illegal dealers might be able to detect and deceive surveillance systems. For this reason, the new solution proposed within the NORMA project consists of a network of noise radar with covert and LPI (Low Probability of intercept) surveillance capabilities. The capability of the radar to be operative all weather all days 24 hour per day accomplished with the main characteristic of transmitting noise-like wideband waveforms with imaging capability is a powerful solution to have an LPI land and sea border surveillance also in critical and The main objective of the NORMA project is to implement an innovative solution that addresses the user needs for covert surveillance. In such a scenario, a noise radar network offers the potential for LPI (Low Probability of Intercept) monitoring whilst guaranteeing the imaging and tracking capabilities.

This paper experimentally proves the ability of millimeter wave radar to provide visibility of objects in a fire. The operation of an imaging radar at a frequency of 79 GHz was investigated under various real conditions, including fire with strong flame, dense smoke, and water vapor. Absorption of the radar signal was measured and the results are in accordance with theoretical calculations. The analysis of the experimental results allows us to conclude that there are good prospects for millimeter wave radar in the field of firefighting equipment for vision and navigation.

In this paper we present the statistical analysis of bistatic rural ground clutter for different terrain types. Compared to state-of-the-art analysis we present clutter models for subdivisions of rural environments. Therefore, four measurement campaigns have been carried out during summer of 2019 in four different rural terrain types, namely a field with low vegetation, with high vegetation, plantation of small trees and forest environment representing a typical rural German environment. The measurements have been carried out in the radar relevant X-Band at a center frequency of 8.85 GHz and with a bandwidth of 100 MHz. The distinction of the rural terrain into different types enables a more precise and accurate clutter analysis and modelling of the statistical properties as shown in the presented results. The statistical properties are derived from the calculated probability density functions and the corresponding cumulative density functions for each of the four terrain types from the measured range-Doppler domain data.

In this work we propose a method of clutter deconvolution and modeling using experimentally obtained UWB radar data. The obtained clutter models are then used for random sequence encoding (RSE) of radar-communication (radarcom) signals to achieve clutter-masked transmissions and improve covertness of the scheme. We present the results of clutter modeling from the laboratory data obtained with the software-defined OFDM radar system. We also present the results of communication and radar performance of the radarcom signals created using the derived clutter model. It is shown that this method has the potential to achieve secure communications in adversarial conditions, while simultaneously addressing radar sensing needs.

Evaluation of the sea surface characteristics from remote sensing data by signal analysis methods is of high demand in a variety of applications ranging from marine navigation to ecological monitoring. Here we present experimental results demonstrating the retrieval of the sea surface characteristics from the backscatter signals obtained by slightly modified Doppler SHF radar. Based on a series of experiments we show explicitly that the sea surface monitoring in the coastal zone of about 1 km can be performed by a proposed experimental setup with reasonable accuracy and performance. Moreover, based on a particular series of measurement, we demonstrate how the sea waves velocity field can be reconstructed using a two-dimensional Fourier transform based approach and further analyzed to reveal the contributions of particular wave components.

The generation of synthetic environments is of prime importance for radar performance prediction and radar development. This is the case for maritime radar where realistic sea clutter generation is particularly useful. New detection strategies of small targets in high sea states with very long integration times, as well as the advent of affordable fixed-panels AESA, require adapting the sea clutter generation principles that were used with the previous mechanical scanning radars. This paper presents a method for synthetic clutter generation putting emphasis on a realistic clutter correlation properties reproduction, whether the beam movement is continuous or discontinuous, scanning very rapidly, randomly and even if the antenna beam is stationary.

In this paper, a 2 x 2 antenna array operating at 5.8 GHz is presented for vital signs acquisition using a radar based system, also known as bio-radar. Since these non-contact systems have multiple applications, their front-end design should take into account the monitoring environment of each specific application. In this sense, the antenna design has a crucial role to guarantee the proper integration of the full system, considering different materials. In this work, the antennas were made using upholstery textile materials, in order to integrate the bio-radar system into a car seat cover. This work presents the design of the antenna and the results achieved through measurements in the anechoic chamber.

In the paper, a slot antenna and a Vivaldi antenna are integrated into a technical, three-dimensional knitted fabric. In order to eliminate problematic sewing, side walls of antenna structures are implemented by an artificial magnetic conductor. Hence, the whole antenna structure can be screen-printed using a polymer silver paste. Parameters of the designed antennas were verified by computer simulations.

The paper deals with the development of a wireless charger for small mobile devices (mobile phones, tablets) to be manufactured from a three-dimensional knitted material instead of a common microwave substrate (e.g., FR4). The textile-integrated device is based on the universal Qi standard for wireless charging. Basic attributes of the design are summarized and technological aspects of manufacturing are discussed.

In a presentation, we shall recall about Fano resonance phenomena, make a brief review on Fano resonances found in metasurfaces, and present recently found Fano resonance in a mirrored array of split-ring resonators. It appears due to the direct interaction of lattice and plasmonic modes. The resonance frequency can be changed by changing the period of the array. The high-quality factor of Fano resonance, around 100, has been evidenced experimentally. Possible applications of the Fano resonance will be considered.

The ability to make accurate and repeatable measurements, rapidly and over wide bandwidths, is essential to more widespread use of the sub-millimeter and THz spectrum. This talk gives an overview of the last two decades of advances in this area. We trace the progression from development and construction of the extremely sensitive superconducting heterodyne receivers in the Atacama Large Millimeter Array (ALMA) to the commercial availability of general frequency extension modules for common microwave test equipment up to 1 THz and beyond. We also describe emerging moderate-volume applications for submillimeter-wave and THz sources and receivers, including small satellite constellations for atmospheric modeling and weather forecasting.

The existence of thermal noise in the channel of a MOS field effect transistor was postulated in early work by Klassen and Prinz [1] and since has been wholeheartedly adopted by the CMOS community as a relatively recent review paper clearly indicates [2]. A very similar approach has been adopted by the authors of BSIM series of compact models (for example [3]). However, this approach is not consistent with universally accepted noise models of III-V FETs and HEMT (see for example [4], [5]). In the latter approach, the gate noise behaves as thermal noise while the drain noise reveals behavior consistent with suppressed shot noise [6]. The drain noise is highly suppressed for long gates by a factor of almost 10 while for very short gates the drain noise approaches a pure shot noise [6], [7]. In fact, almost pure short noise has been experimentally observed in 10 nm gate length CMOS devices [8]. A reduction in gate length improves cut-off frequency but also increases drain noise. These two counter-balancing effects explain why for short gate devices expected improvements in MOSFET noise temperatures upon further gate scaling have not materialized. This paper will explore inconsistencies in noise modeling of noise in III-V FETs and MOSFET and it will explain why the noise performance of RF CMOS has reached its natural limits.

This paper investigates the joint exploitation of Wi-Fi based Passive Bistatic Radar (PBR) and Wi-Fi based Passive Source Location (PSL) for drone localization. The inherent features of the two strategies and the results obtained from their comparison on experimental data show an interesting complementarity between them. Following this consideration, a proper sensor fusion strategy combining these two methodologies is investigated in order to achieve improved results in terms of positioning capability. The three strategies (PBR, PSL and sensor fusion) are evaluated against experimental data. The comparison between the use of the sensor fusion approach and the localization based on a single sensor (PBR or PSL) shows the benefits coming from the exploitation of multiple sensors.

In this paper the performance of the Unscented Kalman Filter (UKF) based tracking is investigated for different Sense and Avoid (SAA) flight scenarios. The improvement of the tracking accuracy through integrating the range rate information into the estimation process with UKF is illustrated. The robustness of this method is further evaluated with a data set provided by Airbus, simulating a range of typical approach scenarios with a detection angle of -110° to +110°.

Trajectory prediction and optimization capabilities are considered as crucial part for efficient Air Traffic Management (ATM) operation. One of the key factors that influence onto trajectory prediction is weather situation at the departure and arrival points and along the flight route. In this context it is crucial to utilize widely systems of operative obtaining information about weather hazards for short-term flight trajectory correction. Onboard meteorological radars are powerful and convenient tool for operative data obtaining during the aircraft flight when atmospheric and weather disturbances arise. In this paper possibilities of trajectory correction by providing accurate and operative meteorological data using the onboard radar system are shown and discussed.

A radar task scheduling method, dual-side scheduling (DSS), is proposed in this paper. In this method, the radar tasks are firstly received as an original sequence, then the time window for the task execution is separated into two sides. All the tasks at each side are shifting toward a separator, connected each other head-to-tail without dwell overlaps. The separator is placed at one of pre-set locations, and the random shifted start time (RSST) technique is applied in order to finalize the scheduling: the start time of each task is randomly shifted in its schedulable interval, then the DSS is respectively conducted at each separator. The RSST process is repeated many times, and the resulting schedule with the minimal cost among all attempts is the final solution. Over a broad range of task loading rate, the proposed method shows 1.5 to 6.2 times less costly than the earliest start time (EST), which is a widely used one-side scheduling method. A full cycle of DSS takes a few tens of milliseconds, short enough for real radar applications.

A multistatic active surveillance radar system has been developed under the project name SAMURAI Swiss African MUltistatic Radar Initiative). The system comprises of one TX node and two RX nodes and works at C-band frequencies. A phased array on transmit and digital beamforming on receive enable the radar's scanning capabilities. The system was tested in a two-weeks period taking place in November 2019 in Thun, Switzerland. The system was initially tested in the laboratory, followed by field tests with a radar target simulator and finally a series of drone flights were executed. A specific C-band multistatic target simulator was built in order to fully exploit the system's capabilities. The system allowed to fully test the Doppler accuracy and resolution, Range accuracy and resolution as well as the radar's detection capabilities for different target RCS'.

In recent years passive radar systems research has been increasingly focused on the use of satellite opportunity signals, and DVB-S signals in particular, since these offer virtually global coverage. Several papers have been published recently proving the effectiveness of very simple demonstrators based on COTS. However, conventional architectures struggle to employ coherent channels on the receiver impacting directly in their cost. In this work we show preliminary results for ground targets obtained using a very low-cost non-coherent COTS architecture.

Passive Radars (PRs) are promising emerging technologies to face new security requirements. Satellite illuminators are of great interest due to their nearby global coverage and availability, operating frequencies and waveforms. The main challenges are related to high transmission losses, which limit the coverage areas. An study of DVB-S capabilities as IoO is presented and first results of ground targets detection in a semi-urban scenario are presented. The employment of commercial parabolic antennas for acquiring both the reference and surveillance channel limits the angular coverage and therefore, the scenario of the PR. Results confirmed the feasibility of DVB-S PRs for low range ground target detection and tracking, and pointed out the effects of target echo Doppler spreading along the signal processing chain, whose analysis is a key step towards the proposal of solutions to increase detection performance.

This paper presents the results of passive synthetic aperture radar (PSAR) imaging obtained with barycentric back projection algorithm (BBPA). The main idea of this algorithm is to minimize the number of the ranges of raw radar data used in image reconstruction. The used solution allows to significantly reduce the number of calculation comparing to classical back projection algorithm (BPA) and is easily parallelizable. These opportunities give ability to create a compact PSAR system with SDR device as an analog to digital converter and mobile GPU platform as a processing unit. The used components due to small dimensions facilitate installation on the airplane platform. The presented in this paper results have been obtained using the PSAR data collected within recent APART-GAS measurement campaign which was held on 3-13 September 2019 in Poland. The work described in this paper may contribute to build future PSAR system working in real time conditions.

Synthetic Aperture radar (SAR) is widely used for earth ground imaging and mapping. In most cases the SAR radar is an active device and can be mounted on both air- and spaceborne platforms. Passive SAR imagery based on illuminator of opportunity such as DVB-T, WIFI, or active radar transmitters has been gaining attention recently and some experimental works has been already been shown recently by researchers to public. Simultaneous Active and Passive SAR imaging is the next natural step of development of this technology. In this paper a system which consist of two demonstrators which operate together in both active (C band) and passive (DVB-T band) mode is presented. The first preliminary results of active and passive SAR imaging of the same ground area taken in the same time using small airborne platform have been shown.

The current demands and new challenges in health provide to medical imaging a central position in the investigation techniques in health and medicine. Medical imaging can really be mastered only by considering the issues that lie throughout the production and interpretation chain of images. Recently, the progress in medical imaging has led to the development of sophisticated devices which have greatly improved medical practices. High resolution or high speed devices are typical example of such systems to cite few. However, these systems often, needs compromise between their typical features (for instance a compromise between high resolution and the speed of imaging). These compromises can be broken by using some appropriate and recent signal and image processing techniques. In this tutorial, we will re-visit the main medical imaging systems with some specific focuses and show the contribution of signal and imaging processing in some selected topics.

Magnetic resonance imaging (MRI) using three-dimensional velocity encoding phase contrast methods offers the opportunity to quantify time-resolved 3D blood flow patterns in vivo. This novel imaging technique allowed unraveling most of the fluid-dynamic patterns inside big vessels (e.g., aorta) and heart chambers (ventricles, atria), both in physiological and pathological conditions. 4D

Flow MRI data can have a breakthrough impact on the evaluation, risk stratification and surgical planning in hemodynamic-related pathologies, e.g., cardiac valve diseases, arterial stenos or insufficiency, dilation, dissection or coartaction. However, its applicability in clinics is limited due to the complex post-processing required to extract the information and the difficulty to synthesize the obtained data into clinical useful parameters. One problem is to extract the points located inside the vessel from the regular MRI grid, since the level of signal outside the aorta can be comparable and even grater than inside the vessel. For the time averaged data, the level of noise is smaller but can still exceed the values of velocity components inside the vessel. On the other hand, the known methods of vessel segmentation usually need manual selecting the points located on or near to the vessel boundaries on each of MRI slices and are very time and labour expensive. In this lecture an original algorithm, which automatically selects the points located inside the vessel will be presented. The method is based on the properties of the of the steady Hagen-Poiseuille flow and allows to visualize the flow patterns at different flow sections and different moments of time, calculate the radius and area of the vessel cross sections, the velocity components, flow rates, flow jet angles etc. and estimate the wall shear stresses. To segment the aorta or the pulmonary artery we need to select only one point located inside the vessel. The developed MATLAB code needs 10-12 seconds of PC time to select the points of the MRI grid located near one vessel cross-section and calculate the parameters of the blood flow. Known algorithms need to select some points (5-6) on the vessel boundary at every MRI data slice and yield similar vessel shapes. A software tool is presented which analyzes the row data and provides information along the whole vessel, between two selected cross-sections and in the vicinity of the selected points. We analyzed 25 datasets. We use MATLAB software for post-processing DICOM files, developing the codes and creating a user-friendly interface. The results of calculations with the use of instant and time averaged velocity components will be presented. Currently the 4D MRI data ensures large enough number of points in the aorta or the ventricle cross section to analyze the flow patterns and their changes in time. In particular, we used phase contrast MRI data, which provides time dependent 3 components of the blood flow velocity with the space resolution of approximately 2 mm and time resolution of 10-20 time frames during one heart bit. These characteristics ensure large enough number of points in the aorta, pulmonary artery and the heart in order to segment the lumen and to analyze the flow patterns.

Nevertheless, this time and space resolution can limit the estimation of some important markers (e.g., vorticity, shear stresses) due to inaccurate velocity derivatives computations. Such hemodynamic markers have been linked to degenerations of the endothelial tissue in bicuspid aortic valve diseases, as well as to right ventricle diastolic disfunction, in searching for novel predictors of pathology worsening. In the lecture some methods to understand the accuracy of shear stresses estimation in big vessels (e.g., aorta, pulmonary arteries) will be proposed. In particular, we will also introduce a new accuracy measure for the shear stress and calculate the possible discrepancy with respect to the local direction of the vessel. Also, in vivo blood flow can be determinant in assessing peculiar hemodynamic features or patterns, such as cavitation phenomena. Cavitation assumes a role in depicting non-physiological blood flow due to separation regions and vortex formation. Indeed, the cavitation phenomena was revealed in artificial mitral heart valves (or mechanical heart valves (MHV)) with the use of Doppler ultrasonography and the corresponding signals were registered during the valve closure. One of the reasons for cavitation to occur was assumed to be the formation of vortexes, which low core-region pressure allows this phenomenon to occur. Thus, an accurate quantification of vorticity and vortex region can indicate possible cavitation phenomena. By contrast, no cavitation was revealed in natural human heart valves possibly due to the compliance of the natural leaflets, which reduces the pressure drop and makes the cavitation impossible. According to these evidences and assumptions, the analysis of flow peculiarities in the heart chambers may be pivotal to the understanding of such phenomena; in such a way, 4D Flow could become a novel tool to visualize and quantify in vivo the performances of artificial devices, with respect to physiological blood flow patterns. In this lecture a method to estimate possible cavitation inception in heart chambers from accurate vorticity measures will be proposed. The results of calculations with the use of user-friendly interface will be shown. We will discuss the use of Computer Fluid Dynamics (CFD) for simulations of the entire cardiovascular system and its competition with the 4D MRI approach. It looks that CFD can be useful for investigations of fundamental characteristics of the cardiovascular system. But its using in personal medicine is limited, since the vessel shapes, dimensions, elasticity, blood viscosity vary from one individual to another, are be time dependent and can be determined only approximately. It looks much more productive to use the 4D flow visualization in diagnostics and treatment. Therefore, it is very important to develop new criteria for the diseases diagnosis based on the individual blood flow characteristics and to introduce them into clinical practice. Useful and comfortable interfaces should be developed for automatic vessel segmentation and investigations of the blood flow characteristics.

In the modern protective system the fast and reliable registration of threat signals generated by different sources (explosion, fire, smoke, etc.) and emergency signal transmission to control block of a suppression devices is very important. In this direction number of experimental investigations has been carried out in Georgia, at G.Tsulukidze Mining Institute. The underground experimental base has been used for experiments, where real explosions were generated. For registration the threats signals fast-acting transmitter and receiver modules has been created and used for the experiments to investigate the impact of shock wave overpressure on human body. An anthropomorphic test device Hybrid III 50th was used during testing. To register dynamic load generated during explosion, 7 sensors were installed in different zones of the dummy. Tests were conducted both with the use of the protective system and without it, in conditions when the charge weight was 2 kg, and the distance from the charge to the dummy was 8,5 m. Comparative analysis showed that the protective system, which contains one absorber (may contain several absorbers), reduces the dynamic loads generated in different zones of a human body by 30-50%. The testing were in relevance to the requirements of standards ISO 6184/4 and EN 14373.

This paper presents Electronically Reconfigurable Superstrate (ERES) antenna capable of modifying the shape of the radiation pattern in an uncomplicated way. The approach adopted in this concept is based on switching the state of passive patch elements placed on an additional layer located above a simple microstrip patch antenna. In order to change the area covered by the antenna range, the proposed antenna provides six different configurations with different directions of maximum radiation and various 3 dB antenna beamwidth. The antenna is dedicated to working in the field of Ultra High Frequency (UHF) Radio Frequency Identification (RFID) applications.

Design and numerical characteristics of X-band non-planar full-metal slot reflectarray antenna are presented. The relative bandwidths of 19.6% upon a criteria of 3 dB directivity reduction and 31.2 dB peak directivity are obtained for the proposed reflectarray. The designed reflectarray size is 20λ×20λ and it consists of two panels assembled edge to edge that form non-planar surface. The proposed full-metal reflectarray design allows the use of laser-cutting techniques for antenna manufacturing. Comparison of the proposed non-planar reflectarray with optimized in different frequency range planar ones and a parabolic reflector is carried out.

Low RCS and long range target detection requires larger power aperture product, which can be achieved by phased array antennas with large number of elements. Antennas with Phased arrays with large antenna arrays increases system complexity. Subarray level multibeam architecture with array processing reduces the system complexity and improves the target detection and estimation performance. Subarray configuration plays a vital role in the array processing. In this paper a new framework with multibeam synthesis is proposed along with subarray configuration design methodology. Modified Clustering algorithms are developed to design the optimal subarray configuration. Experiments are conducted with large hexagonal planar array and results are evaluated with several performance metrics to demonstrate the significance of proposed methods

We consider DoA estimation in a monopulse radar system employing a tilted rotating array. We investigate the case of nonzero steering angles, in which case the mapping between the target's azimuth and elevation in the global coordinate system and their counterparts in the array local coordinate system becomes increasingly nonlinear and coupled. Since estimating the azimuth using coherently integrated signals might be difficult because of strong modulation in the difference signal induced by the rotation of the antenna, we develop an iterative approach that alternates between estimating the elevation using coherently integrated signals and estimating the azimuth using unfiltered signals. We also develop a simplified version of the scheme, which employs only one iteration and forms the final estimates by applying simple corrections to results of the first iteration.

Different approaches to development of an auxiliary antenna designated for sidelobe blanking systems are proposed and discussed. In the proposed concepts a set of two antennas having different radiation patterns is utilized in order to ensure good coverage of main radar antenna's sidelobes. The concepts of the auxiliary antenna are evaluated and compared. The results are comprehensively presented and the criteria for selection of the concept are reported.

The innovative concept of nonresonating modes and how this has been exploited to extend the state-of-art of microwave filter technology will be presented in this talk. After a brief introduction highlighting the importance of microwave filters from a system perspective, the main concepts will be gradually explained by using some waveguide as well as planar SIW examples. The general multimode environment of these structures is described step-by-step with several animations, thus significantly easing the understanding of these concepts for both students and non-filter experts. The presentation is then extended to the most various filter technologies, such as conventional coaxial structures, dielectric resonators based architectures, as well as more original mixed technologies. Several manufacturing examples of actual products developed at RS Microwave (Dr Bastioli's affiliation) are going to be presented along this talk, thus also satisfying the more practical taste of an industry audience.

The paper presents a design of broadband coupled-line directional coupler. The wide operational bandwidth has been obtained by the use of a two-section coupler topology. The tight-coupled section has been designed as a section with indirectly coupled conductors, which makes the design easier in comparison the directly coupled multi-conductor lines. The coupler has been designed in a bi-level microstrip technique. Additionally, capacitive compensation has been applied to improve directivity of the coupler.

Novel configuration of the Faraday rotation isolator employing longitudinally-magnetized ferrite coupled line (FCL) is realized by connecting two lines with a resistor at the end of the ferrite section. The scattering parameters of this microstrip structure obtained through circuit and normal mode analysis providing information for practical design of the isolator. The nonreciprocal behavior of the isolator and its dependence on resistor parameters is reported.

In general, a millimeter-wave component is expensive to fabricate, then, it is an entry barrier of small- and medium-sized enterprises to millimeter-wave industries. Thus, we developed an additive manufacturing (3-D printing) technology for a cost-effective fabrication method of waveguide components in W-band. This report explains a fourth-order Chebyshev bandpass filter is fabricated based on polyamide 11 substrate and conventional nickel electroless plating and copper electroplating technology. The filter has a bandwidth of 7.2 GHz and an insertion loss of 1.4 dB at the center frequency of 87.75 GHz. We confirmed the proposed method contributes cost-effective, light-weight, and easy to manufacture millimeter-wave components.

This paper studies an integration concept for a self-biased Ka-band circulator. Non-reciprocity is achieved by means of a pre-sintered scandium substituted barium hexaferrite which, as a hard-magnetic material, does not require external magnetic biasing. The ferrite is integrated into a microstrip circuit on a RO4000 laminate. This yields a compact and potentially low-cost circulator. The basic functionality is demonstrated in a first experiment. The results are still quite preliminary, though. Yet, some important conclusions can be drawn regarding the required design optimization measures.

Electromagnetic (EM) simulation is the single most important tool in the design of modern antenna structures. Its versatility and reliability comes at a price of considerable evaluation cost, which may be impractical or even prohibitive when multiple simulations are to be executed, e.g., pertaining to parameter tuning or uncertainty quantification. Fast replacement models (or surrogates) may mitigate this problem but modeling of antenna characteristics is a challenging endeavor due to their nonlinearity and typically high-dimensionality of the parameter space. Conventional data-driven modeling methods fail under such circumstances. In this paper, a novel technique is presented which combines the nested kriging framework and variable-fidelity computational models. The former is employed to confine the surrogate model domain to a region containing designs that are of high-quality from the point of view of the considered performance figures. This dramatically reduces the number of required training data samples. Incorporation of low- and high-fidelity simulations is realized using co-kriging. The proposed approach is illustrated using a wideband monopole antenna modeled for wide ranges of substrate permittivity (2.0 <= eps <= 5.0) and height (0.5 mm <= h <= 1.5 mm). Benchmarking indicates that constrained variable-fidelity model outperforms both the conventional surrogates but also the constrained surrogate constructed using high-fidelity EM data only.

Electromagnetic (EM)-driven adjustment of geometry parameters, often referred to as design closure, is nowadays a mandatory stage of antenna design process. It is executed to improve the system performance as much as possible while taking into account parameter dependencies that cannot be handled by simpler methods (e.g., theoretical models), typically employed at the initial steps of the antenna development. Unfortunately, EM-based optimization is a time consuming task, especially when the quality of the initial design is poor. This paper proposes a novel framework for accelerated antenna optimization. Our methodology involves a database of previously obtained designs, kriging interpolation models, and an iterative correction scheme for design refinement. The incorporation of pre-existing data permits generation of a good initial design as well as rapid optimization entailing the cost of just a few EM antenna analyses. The technique is demonstrated using a dual-band uniplanar dipole antenna. The structure is optimized within wide ranges of operating frequencies (2 GHz to 3 GHz for the lower band and 4 GHz to 5.5 GHz for the upper band). Benchmarking indicates that the proposed approach exhibits improved computational efficiency and reliability as compared to gradient-based warm-start optimization techniques.

Main advantages of employing DVB-S as Illuminator of Opportunity for passive radar is high availability, but the power scattered from targets is really low. In this paper, the design of a surveillance antenna capable of fulfilling the requirements defined by the DVB-S passive radar, is carried out. Detection and tracking capabilities of ground targets are considered. A high gain antenna is required for fulfilling range coverage requirements, together with an azimuth beamwidth that provides the required angular one.

To tackle this challenge, a sectorial beam reflectarray antenna is selected. For designing it, a method based on optimizing the steering of a set of beams that form of the sectorial pattern is proposed. The losses from reflectarray cells are introduced, optimizing the distribution of elements by selecting the best phase for the central one. The reflectarray is designed studying the geometric and feeding parameters and it is simulated in ANSYS HFSS achieving a sectorial beam of 7.8º (azimuth) x 2.6º (elevation) with a gain of 28.5 dBi.

This paper presents a design of a millimeter wave (mm-wave) transmitting device, which integrates components fabricated in various technologies. It is composed of a transmitter front-end integrated circuit, an antenna array, and a silicon lens. The design is outlined with particular emphasis on accommodation of contrary requirements of individual elements and integration of the antenna array with other parts of the circuitry into a single device. The low temperature cofired ceramics (LTCC) multilayer structure was chosen as a platform for integration. LTCC demonstrates good electrical parameters (low losses and relatively low permittivity) in the mm-wave range which facilitates design of an efficient antenna. Additional beam focusing and the gain enhancement is achieved by means of the silicon lens suspended over the antenna on an adjustable fixture. The problem of optimal lens placement for two types of antennas is considered.

In this paper two versions of miniaturized 3D printed, open-ended, ridge waveguide antennas are presented. The air-filled and dielectric-filled antennas have been designed, simulated and measured. Several copies of antennas have been manufactured to investigate the impact of dimensions inaccuracy of 3D-printing technology on return loss parameters. For dielectric-filled antenna tuning process is proposed in order to reduce the impact of printed material permittivity and dimensions spread.

The main goal of the conducted research was to estimate the errors of the radio distance measurements (RDMs) performed by using the DWM1000 modules. Measurement campaigns were carried out in indoor environment, for static cases in four different places, i.e. wide corridor, narrow corridor, sitting room, and building's hall for LOS (Line-Of-Sight) and NLOS (Non-Line-Of-Sight) conditions. Additionally, dynamic measurements in typical classroom were made. For the static scenarios, analysis of RDMs errors were presented. In dynamic case, dependencies between changing LOS/NLOS conditions and simultaneous RDMs increase was noticed.

In the article the concept of the radiolocalization subsystem of VHF communication for aviation VCS-MLAT (Voice Communication System - Multilateration) is presented. The distributed localization system will estimate the position of the aircrafts by the audio signals transmitted in aircraft band (118-136 MHz). This paper presents the measurements to check if voice airband communication can be used to estimate the position. Also main assumptions of the project and describes the structure and scheme of the localization modules are presented. At the end of the article the preparation for the final test in the real environment is concluded.

The article discusses the suitability of the multiwall radio wave propagation model for RSSI reference data preparation for fingerprinting-based indoor positioning applications. Localization system employs Bluetooth Low Energy beacons and mobile device to determine position of the user within the test area. The proposed system uses particle filter algorithm to estimate the user's current position from RSSI measurements and knowledge of reference electromagnetic field distribution computed for each beacon located in the building. The results of the comparison between the use of multiwall and ray tracing propagation models for indoor localization purposes has been shown. The relation between the time needed to prepare mentioned reference data was also demonstrated. Presented results show that for some cases it is possible to use less complex propagation models without losing sufficient localization accuracy but for the benefit of the time and complexity of calculations needed to prepare reference data for presented indoor localization application.

Due to confined spaces and various obstacles e.g. walls, furniture, indoor environment may be considered as a harsh and disturbing in terms of indoor radiocommunication services. The given paper presents FNN (Feedforward Neural Network) method for LOS (Line-Of-Sight) and NLOS (Non-Line-Of-Sight) identification which may support mitigation of such a negative influence. Described FNN architecture was evaluated based on a real indoor measurements collected with the use of the UWB (Ultra Wideband) radio modules.

A hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open space is presented here. The main idea is based on impedance matrix descriptions of the boundary surrounding the discrete computational domain and combine it with external field described analytically. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of the posts or fragments of post which geometry is complex. All the obtained results have been verified by comparison with simulations performed using alternative methods or commercial software.

The electromagnetic modeling principle aided with artificial neural network to designing the microwave wideband elements/networks prepared in microstrip technology is proposed in the paper. It is assumed that the complete information is known for the prototype design which is prepared on certain substrate with certain thickness and electric permittivity. The longitudinal and transversal dimensions of new design are calculated separately using the scale coefficients which are determined from transmission line equation. Next the artificial neural network can be used for final tuning which should take into account the dispersion of microstrip line. The verification of proposed procedure is shown for exemplary planar UWB balun.

A fully automated reliable greedy multipoint model-order reduction (RGM- MOR) approach is presented. The subsequent block moments added to the projection bases are orthogonalised by means of the Modified Gram-Schmidt method. Although the orthogonalization process slightly increases the computational time, a significant improvement in performance can be observed in projection basis size, the accuracy of the error estimator, and reliability of the whole reduction process, compared to the GM-MOR technique. The improved quality of the error estimator has a significant effect on the size and accuracy of the reduced-order models. Compared to GM-MOR, the new algorithm yields more compact and more accurate models, allowing wideband reduced-order models to be constructed automatically with an accuracy a few orders of magnitude higher than was previously possible. Moreover, the efficiency of the orthogonalization process is increased, by utilizing the parallel computations using the graphic processing units (GPUs).

This talk focuses on electromagnetic waves in connection with boundaries and surfaces, in particular in the case when the material contrast over the boundary is non-conventional, like often in connection with the analysis metasurfaces. The problem will be approached from the point of view of general electromagnetic boundary conditions: conditions that dictate two relations for (a combination of) the normal and tangential components of the electric and magnetic vector fields at the surface.

In particular, the concept of a matched wave (a wave with such a polarization and incidence state that it itself satisfies the boundary condition, and as such can exist without causing a reflection) will be discussed and illustrated through examples. The talk draws some material from a recent book, coauthored by the speaker (I.V. Lindell and A. Sihvola: Boundary Conditions in Electromagnetics. IEEE Press, Wiley, Hoboken, NJ, USA, 258 pages. ISBN: 978-1-119-63236-8).

The international union of radio science URSI (Union Radio-Scientifique Internationale) is a non-governmental and non-profit organization with mission to stimulate and coordinate research, applications, and international co-operation in the field of radio science. During the present times, URSI celebrates its centenary. Within its technical activities, URSI is divided into ten scientific commissions, and member commissions operate in 44 countries.

This talk takes a look at the history and present state of URSI, in particular from the Finnish, Scandinavian, and Baltic sea region perspective. The potential of the contributions of Baltic countries into URSI activities will be highlighted.

Synthetic aperture radar (SAR) is widely used for ground and structure imaging, both in two and three dimensions. The author is working on a three-dimensional (3D) imaging method that aims to reduce the flight time and the amount of data collected through the calculation and optimization of a complex radar carrier trajectory, which is a computationally heavy process. This paper proposes a method of pre-calculating the point spread functions (PSF) for specific potential aperture points that can be used later to estimate the PSF for a trajectory, allowing for efficient trajectory optimization. Three coordinate systems are considered and compared in terms of computational complexity and accuracy, and have been proven to be usable in certain applications. The proposed method can facilitate the development of 3D SAR.

Regularized iterative reconstruction algorithms for Synthetic Aperture Radar (SAR) Tomography (TomoSAR), like the ones based on Maximum Likelihood (ML), offer an accurate estimate of the Power Spectrum Pattern (PSP) displaced along the Perpendicular to the Line-of-Sight (PLOS) direction. The recovered PSP is considered as 'good-fitted' or 'appropriate-fitted', since the reconstruction fits correctly enough with the position and density of the objectives in the field backscattered towards the sensor. However, the correct functioning of these regularization approaches is constrained to the proper selection of the regularization parameters. Therefore, for such a purpose, this paper suggests using a criterion based on the Stein's Unbiased Risk Estimate (SURE) strategy. SURE approximates the Mean Square Error (MSE) between the estimated and actual PSP, purely from the measured (observed) data, without the need of any knowledge about the true PSP. Consequently, the proper selection of the regularization parameters corresponds to the minimum SURE value, which guarantees having a 'good-fitted' reconstruction. The experiments are performed in simulated data for different representative cases.

The time and phase synchronization are the important issues that must be addressed for bistatic synthetic aperture radar (BiSAR). The processing of synchronization is discussed in the paper. First, the synchronization scheme of LuTan-1 system is introduced in detail. The test results of ground validation system are illustrated to verify the synchronization scheme in LuTan-1. Then, an algorithm based on frequency offset estimation and iteration processing is also proposed for the noncooperative BiSAR. The proposed algorithms have great application potential for future BiSAR system.

The road surface roughness directly influences the grip and skid resistance of the vehicles. Since these parameters are relevant for the safety of the road users, they have to be continuously monitored to keep track of its changes. The potential of airborne polarimetric SAR to remotely monitor the road surface roughness is investigated in this study using fully polarimetric X-band data acquired with DLR's airborne radar sensor F-SAR. The polarimetric analysis revealed that the anisotropy and coherency matrix (T3) elements are sensitive to the road surface roughness. Additionally SAR backscatter based empirical models for surface roughness estimation were investigated.

A combination of the body-of-revolution and finite element methods is utilized to the analysis of coaxial lines with corrugated rod and wall. Both periodic and non-periodic structures can be investigated. As the structure is axially symmetrical the two dimensional scalar-vector finite element method can be used, which allows for the investigation of complex geometries and is computationally efficient. A generalized impedance matrix at the line ports is calculated from which the scattering parameters are derived. A few examples of corrugated coaxial lines have been analyzed and the results were compared to those obtained from commercial software.

In this paper, a method of analysis of conformal RF components has been proposed. In this approach, modeling of a curved structure is based on mesh deformation of planar objects rather than the construction of conformal geometry at CSG level. Since the model is represented as a 3D mesh, the deformation only requires the calculation of nodes position in the bent structure. The results of the proposed algorithm have been validated with simulation from other software and measurements, whereby method correctness has been confirmed.

Measurements of electric and electromagnetic field for safety controls are made by E field probes, typically with scaling in power flux density, indicating what would be true only for plane propagating waves. This presentation addresses the fact that such measurements at microwave frequencies have to be at a minimum distance from the nearest accessible part of the equipment emitting the field, and describes the different rationales for the validity of the 50 mm distance used since many years with e.g. microwave ovens and industrial equipment. -- Since the emission of electric field energy dominates over that from the magnetic field in high frequency equipment, almost quasistatic E field emission conditions occur, resulting in a much weaker power absorption in human tissues than assumed in the existing safety standards. The phenomena are quantified, and a relaxation of the E field emission limits in industrial standards is proposed for such non-radiating conditions, as is a 150 mm minimum measurement distance in combination with barriers, etc., hindering access.

In this work, an anisotropic FDTD method is introduced to simulate electromagnetic concealment with metamaterials using transformation optics. The theory of the algorithm is derived to support our freely available FDTD code, in MATLAB environment. The algorithm provides the possibility to simulate the transient behavior of the electromagnetic cloaking device. The calculation of the anisotropic material properties of the electromagnetic cloak is reviewed.

Dielectric characterization of materials with a Fabry-Perot open resonator in microwave and millimeter wave frequency bands has been known for decades. However, recent rapid development of 5G telecommunications has prompted attempts to extend its applicability toward higher frequencies, and samples with larger thickness and higher permittivity. It requires, among other things, an accurate electromagnetic model of the resonator, which could account for effects that are not occurring in case of thin low-permittivity samples that have been measured so far. For that purpose, a general concept of the analysis of a Fabry-Perot open resonator with the aid of a plane wave expansion method, which opens the way for rigorous, versatile and computationally effective modelling with the measured samples of any kind, is proposed in this paper.

A combination of mode matching, finite element methods and generalized impedance matrix is presented in a context of propagation problems for open guiding structures. The computational domain is divided into two regions: the first one is a circular cylinder containing whole guiding structure and the second one surrounds this artificial cylinder. The impedance matrix is calculated with the use of finite element method in the first region and fields outside are expressed by analytical functions. As a last step propagation coefficients are obtained with the use of global roots and poles finding algorithm. The results for simple dielectric ridge waveguides are presented and compared with alternative solutions.

This paper presents a new approach to plane wave injection in FDTD, which is based on total-field/scattered field (TF/SF) formulation. Six-faced box is used to ensure appropriate boundary conditions for injected plane wave. In relation to TF/SF and G-TF/SF methods, in the proposed approach a number of utilized TF/SF faces is reduced from 6 to 1-3, depending on direction of wave vector of the generated plane wave. Such an approach provides a significant gain in computer resources required for simulation.

In this paper hybrid method for electromagnetic (EM) modelling of coherent radiation in semiconductor lasers is presented. Described approach consist of drift diffusion (DD) model and electromagnetic simulation. Four-level two-electron atomic system with Pauli Exclusion Principle (PEP) extended by electric pumping ratio has been used as lasing model.

The paper presents an open access software platform for electromagnetic (EM) teaching and dissemination of microwave technology results. The platform is developed within the H2020 MMAMA project. Its core is a licence-free GUI, wherefrom different EM and multiphysics solvers can be launched, under different licence schemes. The tools are supplemented with an expandable database of modelling examples and results, documented in the standardised MODA and Gwyddion formats. The presented examples range from the Basic Microwave Course, whose elements have been used for 25 years in teaching at the Warsaw University of Technology, to the modelling of calibration standards for microwave microscopy of materials.

Phase noise (PN) is one of the most significant impairments adversely affecting the detection performance of frequency-modulated continuous wave (FMCW) radar systems. Due to the rapid advance of advanced driver assistance systems (ADAS), virtual testing and the evaluation of highlyautomated driving (HAD) functions became indispensable. In this work, the impact of PN on the performance of automotive radar sensors is demonstrated on HAD functions in a virtual driving simulator. Therefore, a PN model initially developed for static objects is applied to dynamic scenarios including moving objects. By implementing a real world scenario in the virtual environment the influence of PN on the detection performance of the radar sensor is demonstrated. The virtual test scenario is implemented using the CarMaker test driving software, which is commonly accepted as an accurate and reliable tool by the automotive industry. The radar sensor model including PN is implemented as a functional mock-up unit (FMU) using the standardized functional mock-up interface (FMI) 2.0 and the open simulation interface (OSI) 3.0.0. Finally, the radar FMU model simulations are compared with hardware measurements.

For in-depth validation of automotive radar sensors tailored radar test systems are required. Radar echo generators are core elements of those test systems and generate artificial objects with a certain distance, velocity, size and angular direction for evaluating the performance of radar sensors with respect to a known reference. With state-of-the-art sensors that use modern and sophisticated signal processing and modulation schemes, new challenges regarding test and validation setups occur. Especially the generation of artificial reference objects for MIMO radar sensors is challenging, due to the large aperture of the typically utilized phased array and the high sensitivity of this sensors regarding phase deviations. This paper investigates the effect of measurement geometries and the antenna configurations of radar echo generators on the measured angular accuracy of automotive radar sensors that rely on MIMO radar signal processing algorithms. The paper concludes with recommendations for MIMO radar test setups that incorporate radar echo generators.

Modern cars are equipped with many comfort and safety functions like for example Blind Spot Detection (BSD), Lane Change Assist (LCA) or Auto Cruse Control (ACC). Sensors used to support those functions are radars, cameras, ultrasonic and lidar. The forecast is that more and more cars in the future will be equipped with multiple sensors. Automotive radar is an important sensor that provides high quality measurement of range and velocity independent on weather conditions and sun illumination. The expectation is that the amount of cars equipped with radar sensors will increase as functions will be available not only for premium but also for middle price cars and with development of quasi-autonomous and autonomous driving. The number of radar sensors on a single car will also increase as more and more functions are supported by radar. With the increasing number of radar sensors on the road, the topic of interference mitigation will gain more importance. Publicly funded project IMIKO-Radar - Interference Mitigation by Cooperation in Radar for Autonomous Electric Cars investigates automotive interference and various mitigation possibilities. In this paper we will describe automotive radar interference measurements and present first results.

When integrating automotive frequency modulated continuous wave (FMCW) radar sensors for driver assistance systems into the vehicle, the radar sensor cover must be taken into account. Particularly metallic paints on polymer covers lead to high reflections, which impair the radar performance. Therefore, paint properties, which may influence the electromagnetic wave radiated by the sensor, have to be analyzed in realistic experimental setups. Within this paper we show by measurements around 80 GHz that the relative permittivity increases exponentially with increasing pigment volume concentration of the metallic pigments. In general, finer metallic pigments lead to higher relative permittivities. However, very fine pigments may agglomerate and therefore show behavior comparable to coarse pigments. In addition we could show that the type of painting method must be taken into account.

Density Based Spatial Clustering of Applications with Noise (DBSCAN) is the widely used clustering algorithm for automotive radar applications. Many modifications have been proposed across literatures. This paper discusses the most effective method of DBSCAN implementation for High resolution radar applications. Modification of the DBSCAN algorithm for computation and memory optimization especially for an embedded application is discussed in detail in this paper

In order to develop safety-reliable standards for IoT (Internet of Things) networks, appropriate tools for their verification are needed. Among them there is a group of tools based on automated symbolic analysis. Such a tool is Tamarin software. Its usage for creating formal proofs of security protocols correctness has been presented in this paper using the simple example of an exchange of messages with asynchronous encryption between two agents. This model can be used in sensor networks or IoT e.g. in TLS protocol to provide a mechanism for secure cryptographic key exchange.

In this study, the new architecture of the optical switching fabric is proposed. The banyan-type switching networks, well known in switching theory, are composed of symmetrical dxd switches. The new architecture considered in this study is built from mostly asymmetrical optical switching elements. It is shown that the new proposed structure requires a fewer number of passive as well as active optical elements than the banyan-type switching fabric of the same capacity and functionality. It also contains one stage fewer, which, from the optical switching point of view, is an important feature as well.

One of the recent approaches for improving capacity of future wireless network is to increase the density of nodes by deployment of short-range base stations called small cells. When the number of such nodes is high, one may think of so-called ultra or extreme dense networks. In such a case, the efficient management of consumed energy is crucial. In this paper, we discuss the concept of transmit profile selection applied in dense wireless networks. Each profile is defined by the tuple of certain parameters which specify the transmit characteristics of each node, and in consequence allows for assessing total power consumption. Two power profiles has been defined, where one considers transmission using advanced channel coding algorithms and the other utilizes simple modulation schemes with no channel coding. Computer simulation has been performed to compare the performance of the network operating in one of these modes.

Deployment of small cells in heterogeneous network is directly related to the problem of right user association between macro- and small-cell base station. In order to force just selection of appropriate base station, additional component is added to the measured path loss (signal strength) in order to modify, i.e. virtually extend or squeeze, the cell radius. In this short paper, the authors present the concept of using the Cell Range Extension parameter in coordinated LTE-A networks. Within the coordination area that covers numerous base stations, the values of CRE are tuned in such a way that the achieved network throughout is improved. It is to improve network throughput by proper user assignment to the BS.

Monitoring volumetric water content (VWC) at several depths in the soil profile can be performed using either a few soil moisture sensors placed at various depths or a profile probe. The use of a profile probe is less disturbing to the soil, less laborious more convenient, and more cost-effective. The objective of the paper is to estimate the dependence of the depth of the sensitivity zone of a single section of a profile probe working in the time-domain transmission mode (P-TDT probe) on the probe's diameters. This issue was assessed with the use of the finite element method (FEM) simulations in the frequency domain. The scattering parameters matrices obtained in the simulations were transformed to the time domain. Based on the results, the depth of the sensitivity zone was estimated for different probe diameters. It was concluded that the effective soil volume measured by the profile probe of a given geometries is in range 14.3 to 30.9 mm around the tested probe.

Describes a method for measuring the equivalent reflection coefficient of feedthrough power standards. The analysis of measurement error and comparisons of results against other methods is done. The proposed method is universal and does not depend from design of feedthrough power meter.

We present a method for temperature-dependent calibration of a multichannel measurement system for 0.05-3 GHz characterization of material complex dielectric-spectrum. This system, described elsewhere, is based on one-port vector-network-analyzer measurements of a two-port coaxial-cell terminated with a variable load. The nominal system calibration uses multiple coaxial transmission-line sections terminated with a variable termination, and due to a large number of calibration standards is difficult to implement in a multichannel system at multiple temperatures. Therefore, we devised a new variable-temperature calibration approach. In this approach we assume that the temperature variation causes only small changes of the system calibration coefficients, and determine those changes with approximate calibration techniques requiring a lower number of calibration standards. We verify our approach based on measurements of PTFE samples at temperatures from 0 to 40 degrees Celsius.

A commonly used strategy for removing clutter from weather radar echoes is to employ Fourier processing to eliminate the zero-velocity Doppler moment and subsequently re-transforming the residual frequency domain signal back into time domain. This method, though in common use, increases the computational load and it also tends to reduce the signal-to-noise ratio of the processed signal. In this contribution, a new method that employs the target properties will be suggested for removing clutter from weather radar echoes using a computationally economic algorithm. This method for filtering weather radar echoes will exploit the temporal properties of the clutter signal and the useful ‚target signal'. The suggested processing algorithm lends itself to easy implementation provided simple 'a priori' knowledge of the temporal characteristics of the signals involved is either known or readily obtained from the radar measurements themselves.

A 94 GHz frequency-modulated continuous-wave radar that is regarded as a base for creating a focal-plane array imaging system has been developed. The key component of the radar is an original receiver module of a simple design and with low local oscillator power requirements. The radar prototype is described and demonstration of its operation capability is presented. The problems of developing a focal-plane array radar are discussed.

This paper presents the design and realization of a Doppler radar system based on a direct digital synthesizer (DDS) operating at 18.5 GHz. The Doppler radar presented here relies directly on the signal generated by the DDS. This represents a major difference to other radar systems, where a DDS is used only for PLL stabilization of a VCO. The specification of the DDS as well as the design of the radar system will be presented here. First Doppler radar measurement results in the frequency band from 5-10GHz will be shown using a speaker membrane as a target oscillating with a frequency of up to 100Hz. The radar system shows excellent performance with a low noise floor and the ability to resolve small frequency differences down to 0.3 Hz. It is also demonstrated that the radar exhibits a perfectly linear ultra-wideband tuning characteristics, which eliminates the need for VCO tuning linearization.

Algorithms for detection and selection of objects of interest in remote sensing observations based on multi-threshold processing are investigated. The studied algorithms convert monochrome images into a set of binary layers which are next subjected to simple morphological analysis allowing for the selection of isolated objects in each layer. By analyzing the location and the geometric characteristics of objects in neighboring layers one can generalize the selection procedure by applying objective geometric criteria to the multi-layer scene reconstruction based on the percolation effect. This way adaptive threshold can be selected individually for each object of interest leading to a significant reduction in the false alarms rate during detection especially at lower-level thresholds where high hit rates can be achieved. The efficacy and performance of the approach is supported using both simulated random fields as well as television and radar remote sensing observations.

The amount of space debris orbiting around the Earth has seen a dramatic growth through the recent years. This growth is fed by an avalanche multiplication process. In fact, according to the ''Kessler syndrome'', any collision generates more debris that then collide with other objects and produce further debris. This growth represents a serious hazard for operational spacecraft, human activities in space and even the Earth environment since their re-enter is uncontrolled. Thus, it is important to continuously monitor and characterize them. Instrumental features for their characterization are surely represented by their size and spin rate. Inverse Radon transform (IRT) tool has been proved to be a valid solution for this task. In this paper, we propose a comparison study between different approaches based on IRT for the estimation of the object's rotation period.

The paper presents the results of studies on analysis, implementation and testing of beamforming methods which can be used for enhancement of radiolocation capabilities of radioastronomical LOFAR station in the context of its use for passive radiolocation. Using the LOFAR system for passive radiolocation might be an highly cost-effective solution for location of objects due to the fact that most of the necessary equipment already exists. In this paper the location of planes by a single LOFAR station in Borowiec was considered as the proof of concept for a more complex system for localizing space objects in the future. The beamforming Phase-Shift algorithm used for passive radiolocation by means of LOFAR station was presented and thoroughly discussed. Beam patterns of steered antenna array of a LOFAR station and its single subapertures, known as tiles, were shown. Occurrence of grating lobes in presented beam patterns is also discussed. The results of preliminary experiments performed with real signals registered by the LOFAR station in Borowiec confirm the efficiency regarding enhancement of radiolocation capabilities, increasing radar's range and certainty of detection by means of beamforming.

We would like to invite all the participants of the conference to join the presentation about emotions in our life, and how to deal with them and as a result manage stress.

Emotions are states connected with pleasure or unpleasantness. They are also reactions to the positive or negative stress. We can describe emotions of human beings and animals, and perhaps - also plants.

In general, it is common to believe negative emotions are bad, but we shouldn't forget that they have also positive energy. If our different needs are not fulfilled from the early childhood we don't have the mechanism to develop many emotions at certain level. That could lead us to various psychical and physical illnesses and as a consequence to shorter life expectancy. Therefore it is very important to form our psychological resiliency to stres. That is why special Ego Resiliency Scale was created by Block and Kremen in 1996. Moreover the mechanism of the positive desintegration described by Kazimierz Dąbrowski enriches all human life and broadens horizons of thinking and feeling and can become the inspiration to the creativity in different domains.

The research on Mirror Neurons by Giacomo Rizzolatti is vital in the process of emotion's "contamination". Nowadays, due to the technical progress, many various experiments in this area are carried out with the help of optogenetics e.g. by Phd. Ewelina Knapska from Nencki Institute.

Emotions can cause psychosomatic illnesses, addictions and anyone can be object of manipulations because of emotions. We would like emphasize that the appropriate diet and exercises help us to deal with emotions and influence our behavior in a positive way.

This paper reports the design, manufacturing and test of a power amplifier, based on a newly power bar device developed on GaN technology, conceived for L-Band applications. The realized active device is a single 10mm active periphery GaN HEMT, realized by paralleling eight 1.25 mm-gate periphery devices (10x125μm), fabricated on a 0.5μm GaN-on-SiC technology by Leonardo company. The power amplifier realized with this device is tested in pulsed condition, demonstrating an output power higher than 40W at 30V of drain voltage supply, with an associated efficiency of 50% at 3 dB of gain compression.

In the paper RF performances and thermal features of GaN HEMTs grown on Si substrate for the design of microwave high-power amplifiers have been briefly presented referring also to the state of the art of the dominant GaN-on-SiC HEMT technology. As GaN-on-Si HEMT application examples driver and final stage amplifiers with high-voltage NPT2018 and NPT2022 transistors made by MACOM were designed and experimentally verified. The amplifiers operate over a 1.2 GHz to 1.4 GHz frequency range with saturated output power nearly 42 dBm and 51 dBm, respectively, at the power added efficiency more than 60%.

This paper presents a wideband class J power amplifier (PA) based on a packaged 10 W GaN HEMT device covering the 3 GHz to 3.8 GHz frequency range. A good trade-off between efficiency and gain has been pursued in synthesizing the second harmonic output termination. The achieved output power is in excess of 41 dBm with drain efficiency ranging from 59 % to 65.5 % and a small signal gain above 14 dB. Preliminary large signal measurements at 3.3 GHz confirm the proper behavior of the PA.

This paper presents a design of highly efficient 3 way Doherty amplifier with CG2H40010 transistors from Wolfspeed. A new power divider is presented that enables the compact Inverted 3-way Doherty architecture to be designed. The amplifier operates over a 3.4 to 3.8 GHz frequency range and reaches up to 46W of saturated output power with drain efficiency of 75% at full drive and 53% at 10dB output power back-off.

This paper presents a Doherty power amplifier working from 3.1 GHz to 3.6 GHz. It adopts 10 W packaged GaN HEMTs from Cree/Wolfspeed and achieves a saturated output power in excess of 43.4 dBm. Saturated efficiency ranges from 57.7 % to 75.2 %, while efficiency at 6 dB back-off is between 44.2 % and 59.8 %. System-level simulations at 3.5 GHz adopting a 16QAM signal with 5 MHz bandwidth and 4 dB PAPR showed an adjacent channel power ratio of -28 dBc/Hz without pre-distortion, at an average output power of 43 dBm and with an average efficiency of 71 %.

As antenna arrays are being deployed in both 5G base-stations and user equipment, phase-shifters have received great attention. This work reviews the requirements for phase-shifters in 5G user equipment and presents ultra-broadband phase-shifting solutions capable of complete coverage of 5G millimeter-wave spectrum.

In this paper an example of the high power diplexer for the phase reference line in proton accelerator is presented. The diplexer operates at frequency 352 MHz and 704 MHz. The output power level is 200 W. Additionally the requirements for the slope of the diplexer phase characteristic have been set at low level. The diplexer consists of two filters realized in the microstrip line technology. To improve the diplexer characteristics a special method has been used in the design. The inverters in the lower frequency passband filter have different electric lengths. The measurements show the low loss, high isolation of transmission bands and phase stable in the passbands thus confirm applied method.

RF SplitBox is a 10-channel signal distribution module designed for use in LLRF control system of the European Spallation Source accelerator. It is designed in two variants, operating at different signal frequencies: 352.21 MHz and 704.42 MHz. The device is constructed from several submodules. Their design is discussed in this paper, with main focus on low-loss and low phase drift RF power splitter circuits. Low phase drift in signal distribution modules is essential for achieving and maintaining required beam parameters in the accelerator. RF SplitBox prototype measurement results are presented.

Crosstalks are one of the limitations of multichannel RF systems. An example of such is the Cavity Simulator project designed by the Institute of Electronic Systems to be used for testing the Low-Level Radio Frequency (LLRF) control system in the European Spallation Source (ESS) in Lund. This device contains 7 RF outputs interfering with each other, resulting in a limited dynamic range.

To resolve the issue of crosstalk, a solution, where a pre-distortion signal is added to all channels, was proposed. The concept was tested, but the solution required manual reconnecting of RF cables and took a significant amount of time. Based on the first results, a solution with automated signal switching was proposed. It is based on an additional module that is integrated with the Cavity Simulator hardware.

This paper present the proposed solution for the RF front-end used in the automated crosstalk correction system for the Cavity Simulator project. The overall system concept and the detailed design of the crosstalk correction module are shown.

This document presents a realization of an analog voltage driven 3 GHz phase shifter circuits for the phase reference distribution system (PRDS) that is currently under development by the Institute of Electronic Systems (ISE) for SINBAD (Short Innovative Bunches and Accelerators at DESY), in Hamburg. Presented phase shifter structure is based on a topology of a reflection phase shifter, made with a 3 dB hybrid coupler structure and varactor diodes acting as adjustable reflections. The realization is planned to be used as a substitute for obsolete phase shifter ICs and for this reason the area taken by the phase shifter in the PCB should be small. That is why we decided to use commercially available LTCC hybrid couplers, which allow widening the frequency band that can be covered by the phase shifter, area reduction and maintaining good return loss and insertion loss of the device, which is of utmost importance in SINBAD PRDS.

Highly automated driving functions currently often rely on a-priori knowledge from maps for planning and prediction in complex scenarios like cities. This makes map-relative localization an essential skill.

In this paper, we address the problem of localization with automotive-grade radars, using a real-time graph-based SLAM approach. The system uses landmarks and odometry information as an abstraction layer. This way, besides radars, all kind of different sensor modalities including cameras and lidars can contribute. A single, semantic landmark map is used and maintained for all sensors.

We implemented our approach using C++ and thoroughly tested it on data obtained with our test vehicles, comprising cars and trucks. Test scenarios include inner cities and industrial areas like container terminals. The experiments presented in this paper suggest that the approach is able to provide a precise and stable pose in structured environments, using radar data alone. The fusion of additional sensor information from cameras or lidars further boost performance, providing reliable semantic information needed for automated mapping.

This paper presents a detailed investigation of the scattering mechanisms occurring at different traffic signs and a guide post in the 77 GHz automotive radar frequency band. By utilizing a polarimetric ISAR imaging process the scattering centers are spatially resolved in a 2D image plane. The proposed phase drift compensation approach provides the basis for a valid analysis of scatterers. A potential vehicle self-localization relying on such landmarks will benefit from this knowledge.

When adapting SAR (synthetic aperture radar) techniques to vehicles it becomes obvious, that there are some dramatic differences to air-born SAR systems. The main difference in automotive applications is, that vehicles does not drive with constant speed in straight direction only as planes do. Therefore in this paper a novel algorithm is developed what enables to estimate vehicles ego motion very precisely and at exactly those time steps when it is needed. This algorithm enables both, generating SAR maps as well as autarkic ego motion estimation. Tests in real traffic scenarios show promising results.

Fundamentally, automotive radar sensors with Digital-Beamforming (DBF) use several transmitter and receiver antennas to measure the direction of the target. However, hardware imperfections, tolerances in the feeding lines of the antennas, coupling effects as well as temperature changes and ageing will cause amplitude and phase errors. These errors can lead to misinterpretation of the data and result in hazardous actions of the autonomous system. First, the impact of amplitude and phase errors on angular estimation is discussed and analyzed by simulations. The results are compared with the measured errors of a real radar sensor. Further, a calibration method is implemented and evaluated by measurements.

In automotive radar applications, the compressive sensing (CS) based DoA estimation is used in array signal processing in recent years. Sparse reconstruction has the potential to estimate the direction of arrival (DoA) with super resolution. However, failed results may be acquired via sparse reconstruction in inappropriate conditions, namely the critical condition determining success or failure must be taken into consideration. In this paper, the sparsity of the scenario and the signal-to-noise ratio (SNR) are analyzed as the main factors via phase transition diagrams. Other factors affecting the success or failure are also investigated, such as the array configuration and the sparse recovery algorithm. Simulated and experimental results demonstrate the critical conditions, in which the DoA estimation is successful or failed.

Time Domain Transmissometry (TDT) is one of the methods of electromagnetic metrology. This method, similarly to TDR, is mainly used to measure parameters of transmission lines and connectors. It is also suitable for determining the dielectric properties of materials from which the transmission line is built. It is known that water has a high dielectric permittivity of about 80. This means that the volumetric water content of the soil has a decisive influence on its dielectric properties. A transmission line placed in the soil can be a detector of dielectric properties and then soil moisture. For these reasons, the TDR and TDT methods are commonly used to measure and monitor soil moisture. The selection of materials shape and construction of the transmission line are a constant challenge for the sensor designers. The probe's construction should be watertight and materials used for construction should not absorb water. The paper presents selected research results concerning the design of soil moisture sensor and signal analysis to determine bulk dielectric permittivity.

Dielectric sensors operating in time and frequency domain can be used to determine soil moisture content. There is still a need for developing new sensors for determination of soil water content, in order to further improve measurement accuracy, lower the price or adapt the equipment for special applications. For example, many of the existing soil moisture probes do not allow precise measurement of dielectric properties in a small volume because of their construction. The paper presents the evaluation of a seven-rod probe for an accurate determination of soil water content in a small sample volume. Firstly, digital simulations for sensitivity zone of the tested probe were performed. Next, the prototype probe was tested for two soils with various texture and moisture content in the range from air dry to near saturation. The values of dielectric permittivity (frequency domain) and apparent dielectric permittivity (time domain) were calculated from the measured S11 parameters. The obtained data was compared with the reference Topp's equation. It was concluded that the tested probe is able to accurately measure soil moisture in a small volume in the range of frequencies from 20 MHz to 200 MHz.

The work presents test results of an open-ended probe with an antenna (OE-A) as a tool for the measurement of soil water content. The measurement volume of OE-A is larger compared to a classical coaxial open-ended (OE) probe, making the considered probe applicable in agrophysics. To correctly assess the reliability of the probe, both numerical simulations and measurements were done. Two types of the mineral soils with different moisture were analyzed in the frequency range 1 MHz - 6 GHz using vector network analyzer (VNA) one port (reflective) measurements.

We present a wideband characterization of soil complex dielectric permittivity spectra in the frequency range from 40 Hz to 500 MHz. Soil samples of various moisture content were measured with the use of a seven-rod probe, which was connected to an impedance analyzer and a vector-network-analyzer through a switch controlled by a PC. The use of a single probe in connection with both analyzers ensured that the same samples were examined in the whole frequency range, without the density changes nor significant moisture variations between the consecutive measurements by the analyzers. The spectra obtained from both instruments were merged and analyzed with the use of a combined permittivity and conductivity model.

Water as the precious resource necessary to sustain life on the Earth should be used in the sustainable way. This is especially important to that part of water that directly affects living organisms, that is soil water. Its total volume is about 0.001% of total water on the Earth but its importance in the habitat of all living creatures is priceless especially for food production and climate regulation. Therefore, soil water amount and quality should be monitored in automatic and non-invasive way. The paper presents electromagnetic methods and sensors for monitoring soil water content. Special attention is put of the respective microwave tools, their advantages and prospects for the future of soil moisture metrology.

Detection and localization of physical radiating sources allows to allocate hotspots with substantial emitting power on the surface of the printed circuit board (PCB) of the electronic device. Electromagnetic emissions caused by data transferring signals can be mathematically described by cyclostationary stochastic processes. The optimal detection of cyclostationary stochastic process with known two-dimensional autocorrelation function (ACF) assumes two-dimensional cross-correlation between the shifted product of the stochastic process and relevant ACF. The proposed detection algorithm is based on the degree of cyclostationarity (DCS), defining by comparison of evaluated ACFs obtained from the measured realizations of stochastic process. Experimental verification of the proposed algorithm was implemented by near-field scanning of two spatially distributed sources with different cyclic frequencies on the surface of the PCB.

Estimation of statistical characteristics for radiated electromagnetic emissions caused by PCB can be implemented by statistical signal processing of time domain signals measured by near-field scanning system. The relation between the source signal and the signals measured by the near-field probe at each scanning point can be modelled by linear transformation of the source signal. In this paper modeling procedure for near-field to far-field propagator based on Jefimenko's equations is presented. Radial component of instantaneous power density represented by Poyting's vector was derived from the modelled electric and magnetic far fields components. Synchronized impulse responses can be used for computer aid prediction of the spatial-time evolution of the cyclostationary characteristics in the environment surrounding the PCB. The 2D periodic ACF of the far-field shows the cyclostationary properties similar to the properties of initial random bit sequence.

Antennas belong to the key components of wireless communication devices. Strict design specifications imposed on modern systems can be fulfilled only by complex antenna structures. Their computational models have to be of high fidelity to ensure reliability, i.e., sufficient agreement between simulations and physical measurements of the fabricated prototypes. A prerequisite for that is utilization of full-wave EM analysis but also incorporation of the peripheral components. EM-driven design of high-fidelity models using conventional optimization algorithms is often impractical due to high computational cost entailed by a large number of simulations required to find a desired solution. In this work, a low-cost optimization of antenna structure with peripheral components is discussed. The performance of the presented approach is demonstrated using a bandwidth-enhanced quasi-patch antenna optimized to maximize the gain while maintaining acceptable in-band reflection. The results indicate a fifty-percent reduction of the design cost compared to a benchmark algorithm.

Wireless Body Area Networks operate in the proximity of human body. This is complex environment that affects the operation of wearable antennas changing their input impedance. This effect can be simulated with numerical models of human body. For the sake of prototype antenna measurements the physical model is used that should correspond to the numerical one as well as to the body of human subject. In this paper a simplified numerical and physical model of human body for antenna input impedance analysis is presented. It is suitable for computer simulation because it has reduced size and complexity. At the same time, its physical equivalent is easy in fabrication due to the selection of available materials. The results of numerical simulations and measurements of antenna impedance mismatch performed with this model are in good correspondence to the results of measurements obtained with human subject.

A new architecture for a widely distributed dual-band coherent multiple-input multiple-output (MIMO) radar system is illustrated, and its implementation and testing are reported. The system consists in a central unit based on a single mode-locked laser, supporting multiple remote radar nodes linked by standard optical fiber pairs. Every remote node operates both in the S- and X-band, and it can be displaced over distances of several kilometers, allowing to monitor a scene under different angles of view. All the remote nodes share the same oscillator and digital signal processing unit, both located in the central node. This architecture allows to perform centralized data fusion on the signals acquired by the remote nodes, and, by virtue of the system coherence, to take advantage of the coherent MIMO processing strategy thus to offer a superior spatial resolution, which is even magnified by the dual-band approach.

A method of 3D velocity measurement based on an integrated MIMO radar is presented. The method is based on cross-correlation in range and cross-range, making use of the spatial distribution of the antenna aperture. Using measurement data 3D velocity measurement with a relative error of less than 5% is shown being suitable to compensate for drift effects which limit the performance of IMU based motion detection systems.

The article deals with the technology of construction of nonparametric processing methods of correlated random processes. The use of a Markov model of correlated signals allows to synthesize the nonparametric rank algorithms. The theory of synthesis of nonparametric rank Markov decision rules is constructed, the problem of synthesis of rank nonparametric algorithm for detection of correlated signal against the background of uncorrelated noise on the output of amplitude demodulator is solved. Property of this algorithm is investigated

One of the primary challenges for an Electronic Support (ES) receiver is interception and analysis of low probability of intercept (LPI) radar signals, which for example are linear frequency-modulated (LFM) signals. In the paper detection and estimation of LFM waveform parameters based on the extended forms of the standard cubic phase function (CPF) is proposed. Originally the CPF function was introduced for instantaneous frequency rate (IFR) estimation. Extended forms are created by summation operations or multiplication operations, or integration operations of the time slices of the standard CPF function. The CPF function and its extended forms concentrate energy of LFM waveforms along a IFR line in the time-chirp domain just as the short time Fourier transform (STFT) and Wigner-Ville distribution (WVD) concentrates energy of LFM signals along an instantaneous frequency (IF) line in time-frequency domain. Based on the extended forms of the standard CPF function, test statistics have been proposed and intensively evaluated in Monte-Carlo simulations. Selected results of investigations on parameter estimation and high detection efficiency obtained by the proposed methods are presented.

High frequency Over-the-Horizon Radar (OTHR) provides an economical means to track non-cooperative air targets over large expanses of land and ocean. Because of dynamic ionospheric conditions in polar regions, any OTHR would necessitate a system where the operating frequencies and elevation angles change periodically to maintain constant detection of targets downrange. In this regard, an accurate electron density model is necessary for the purpose of improving operational OTHR and OTHR planning/design. Observations over recent years have established that large-scale electron density structures are a common feature of the polar cap F-region ionosphere. These structures take the form of convecting patches and arcs of enhanced electron density which form tilted reflection surfaces for HF radiowaves, allowing off-great circle propagation paths to be established. Numerical ray tracing has been employed to simulate the effects of these structures on the ray paths of the radiowaves. The effect of frequency monitoring system for OTHR due to the presence of patches of enhanced electron density within the polar cap ionosphere has been studies in this paper.

Modern linear particle accelerators are large-scale facilities utilizing normal and superconducting microwave resonator cavities to increase energy of physical particles such as electrons or protons. Particles travel at velocities comparable to the speed of light through the cavities and high-gradient Electro-Magnetic fields must be extremely precisely amplitude and phase controlled in order to assure proper acceleration of the particle beam. Sophisticated accelerating field controllers and beam diagnostic systems require synchronization reaching tens of femtoseconds in time domain or 0.001 degree in phase at RF frequencies. In larger accelerators like the E-XFEL in Hamburg, there are several thousands of synchronized devices distributed along 3,4 km long machine. This talk will cover challenges and solutions used to distribute RF synchronization signals in large scientific machines, including control of phase noise and phase drift in components of the synchronization system.