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On-wafer measurements are of fundamental importance to the characterization of active and passive devices at millimetre-wave frequencies. They have been commonly known to be ambitious and challenging due to the occurrence of parasitic effects originating from probes, multimode propagation, crosstalk between adjacent structures and radiation. While a lot of investigations have been performed for conventional coplanar waveguides (CPW) measured on ceramic chucks, the parasitic effects occuring in conductor-backed CPWs (CB-CPWs) have not been fully understood yet. Therefore, this paper presents a thorough study for CB-CPWs based on electromagnetic simulations. Additionally, this paper proposes an analytical description accounting for the probe geometries to predict the occurrence of resonance effects due to the propagation of the parallel-plate-line (PPL) mode. For the first time, a new analytical description including the effects of the probe geometries is presented and validated by both measurements and simulations.

Dual linear polarization microstrip antenna configurations are very suitable for high-performance satellites, wireless communication and radar applications. This paper presents a new method to improve the co-cross polarization discrimination (XPD) for dual linear polarized microstrip antennas at 10 GHz. For this, three various configurations of a dual linear polarization antenna utilizing metamaterial unit cells are shown. In the first layout, the microstrip patch antenna is loaded with two pairs of spiral ring resonators, in the second model, a split ring resonator is placed between two microstrip feed lines, and in the third design, a complementary split ring resonators are etched in the ground plane. This work has two primary goals: the first is related to the addition of metamaterial unit cells to the antenna structure which permits compensation for an asymmetric current distribution flow on the microstrip antenna and thus yields a symmetrical current distribution on it. This compensation leads to an important enhancement in the XPD in comparison to a conventional dual linear polarized microstrip patch antenna. The simulation reveals an improvement of 7.9, 8.8, and 4 dB in the E and H planes for the three designs, respectively, in the XPD as compared to the conventional dual linear polarized patch antenna. The second objective of this paper is to present the characteristics and performances of the designs of the spiral ring resonator (S-RR), split ring resonator (SRR), and complementary split ring resonator (CSRR) metamaterial unit cells. The simulations are evaluated using the commercial full-wave simulator, Ansoft High-Frequency Structure Simulator (HFSS).

Switched-mode power supplies (SMPS) convert an input DC-voltage into a higher or lower output voltage. In automotive, analog control is mostly used in order to keep the required output voltages constant and resistant to disturbances. The design of robust analog control for SMPS faces parameter variations of integrated and external passive components. Using digital control, parameter variations can be eliminated and the required area for the integrated circuit can be reduced at the same time. Digital control design bears challenges like the prevention of limit cycle oscillations and controller-wind-up. This paper reviews how to prevent these effects. Digital control loops introduce new sources for dead times in the control loop, for example the latency of the analog-to-digital-converter (ADC). Dead times have negative influence on the stability of the control loop, because they lead to phase delays. Consequently, low latency is one of the key requirements for analog-to-digital-converters in digitally controlled SMPS. Exploiting the example of a 500 kHz-buck converter with a crossover frequency of 70 kHz, this paper shows that the 5 µs-latency of a ΔΣ-analog-to-digital-converter leads to a reduction in phase margin of 126°. The latency is less critical for boost converters because of their inherent lower crossover frequencies. Finally, the paper shows a comparison between analog and digital control of SMPS with regard to chip area and test costs.

Capsule endoscopy is a promising diagnostic tool for the entire gastrointestinal tract. Since a patient swallows the capsules, their size must be sufficiently small. The principal built-in components are cameras, silver-oxide batteries, light emitting diodes, and an antenna for transmitting the video. For diagnosis and treatment, the precise localization of the capsules for specific video frames is required. Recently, static magnetic localization of these capsules with an integrated permanent magnet showed promising results. However, in the state-of-the-art, relatively large magnets compared to the small capsules were used. Therefore, in this extended paper, the localization performance of a recently proposed optimized differential static magnetic localization method for different sized disc and ring magnets was evaluated. The ring magnets were designed for integration with the two batteries of commercial capsules. The magnets were evaluated in static and dynamic scenarios to evaluate the performance of the method in a patient's daily life. It was revealed that the mean position and orientation errors did not exceed 5 mm and 4∘, respectively, for all applied magnets except for the 1.5 and 3 mm long disc magnets. Moreover, the results indicated that the ferromagnetic batteries of capsule endoscopes increase the localization performance when they are centered within a diametrical ring magnet. Overall, it was revealed that the localization performance of the optimized differential method is significantly better than the state-of-the-art even when the magnet volume is significantly reduced compared to previous work. Therefore, it was concluded that 5 mm long disc magnet or a ring magnet are excellent candidates for integration into a commercial capsule for magnetic localization and yield the advantage of being passive magnetic sources.

In recent years, the fast construction, expansion and repowering of wind parks have been a major source of concern for the weather radar community and meteorological services. Among others because wind turbines are extremely tall, reflective, and moving objects, which make them a source of interference that is hard to distinguish from meteorological echoes and therefore difficult to filter and even more difficult to correct. Polarimetric C-Band Doppler weather radar measurements enable us to analyse and understand the impact of wind turbine interference on meteorological weather radar echoes and to build up knowledge. The main idea is to analyse the raw IQ-data in order to quantify the behaviour of wind turbine interference with meteorological scattering. As a first step in this direction, this paper will focus on the derivation and analysis of radar moments such as Reflectivity (Z), Differential Reflectivity (ZDR), Differential Propagation Phase (PHIDP), Mean Doppler Velocity (V), and Correlation Coefficient (RHOHV). We will consider two cases: (i) events with precipitation, and (ii) events without precipitation, in order to understand and model the impact of wind turbine interference (WTI). For this purpose, weather radar measurements from Deutscher Wetterdienst (DWD), recorded under the aegis of the project RIWER (Removing the Influence of Wind Park Echoes in Weather Radar Measurements), are presented, analysed and discussed in detail.

Precise position information is important for terrestrial and airborne surveying systems, such as unmanned aerial vehicles (UAVs). Those systems often rely on real-time kinematic (RTK) global navigation satellite systems (GNSSs) for position determination, where the GNSS antenna mounting environment impacts the GNSS position accuracy to a great extent. This paper investigates the impact of different supplementary groundplane shapes, sizes, and materials on multi-band patch and helical GNSS antennas at both, the UAV rover and RTK base station with respect to the achievable position accuracy. The groundplanes consist of solid aluminum sheets or copper plated printed circuit boards (PCBs) and are mounted directly underneath the GNSS antennas. Appropriate supplementary groundplanes are found to significantly improve the GNSS position accuracy in the majority of test cases.

The efficient determination of left eigenvectors in the method of lines (MoL) is described in this paper. The electromagnetic fields are expanded into eigenmodes and the eigenmodes are determined from an explicit matrix eigenvector problem. To study complicated structures with a moderate numerical effort, the analysis is done with a reduced set of these eigenmodes. The enforcements of the continuity of the transverse electric and magnetic fields at interfaces leads to expressions with rectangular matrices. Now left eigenvectors can be considered as inverse of these rectangular matrices. Until now, the left eigenvectors were determined from a second explicit eigenvalue problem. Here, it is shown how they can be determined with simple matrix products from previously determined right eigenvectors. This is done by utilizing the relation between the transverse electric and magnetic fields. The derived formulas hold for structures with Dirichlet, Neumann or periodic boundary conditions and the materials may be lossy. Open structures are modeled with perfectly matched layers (PML). To verify the expressions, various devices that contain such PMLs and lossy metals were studied. In all cases, error measures show that the algorithm derived in this paper works very well.

In the era of automated and connected driving, more and more cars will be equipped with wireless transmission technologies such as mobile communications 4G (LTE) and 5G, WiFi, Bluetooth, and V2X. For the technical implementation of V2X-communications, different standards like cellular-V2X from the cooperation 3rd Generation Partnership Project and ITS-G5, based on the WiFi standard 802.11p from the Institute of Electrical and Electronics Engineers, are under consideration. The electromagnetic environment of cars and the corresponding exposure of the general public to wireless emission will be significantly influenced by new radio technologies. Under all circumstances, it must be ensured that the exposure of the electromagnetic fields inside a car does not cause any harmful effects on humans. In order to quantitatively assess the resulting exposure, the generated exposure must be correctly recorded and evaluated according to their specific time-frequency spectra. This paper describes a new measurement procedure suitable for the V2X-standard ITS-G5 together with various exposure measurements performed in different cars with WiFi, Bluetooth and ITS-G5. In comparison of all wireless standards studied here, the V2X-service generated the highest electric field strengths inside a car, when a transmitting di-patch antenna was mounted on the windscreen inside the driver's cabin. The maximum fraction of the corresponding ICNIRP reference level amounted to 15.1 %. We conclude that the total exposure of wireless on-board automotive devices will be dominated by ITS-G5, if the transmitting antenna is located inside the passenger cabin. As V2X-communications will increasingly penetrate road traffic, the resulting exposure should be carefully monitored, in order not to exceed the corresponding reference levels for general public.

Cooperative sensors allow for reliable detection, classification and localization of objects in the vehicle's surroundings – even without a line-of-sight contact to the object. The sensor principle is based on a communication signal between the vehicle and a transponder attached to the object of interest – a pedestrian, for example. Thereby, localization information is gathered by measuring the round-trip time-of-flight (RTOF) and evaluating the angle-of-arrival (AOA) of the incident signal. After that, tracking algorithms are used to recover the kinematic state of the object providing a basis for situation assessment. This paper investigates possibilities and benefits of extending this principle by the communication of information from inertial sensors which are locally attached to the transponder. Furthermore, this paper presents a robust approach for fusing the localization data with dynamic object information using the Dempster-Shafer theory. The approach is evaluated by performing real-world experiments for the analysis of pedestrian accidents.

In this paper blind equalization algorithms based on digital watermarking are presented. Training sequence is sent along with the data in the form of watermark. Robust CDMA based watermarking algorithm is used to watermark the data. Watermark, which is spread over the data, does not consume extra bandwidth. So with the help of extracted watermark channel can be equalized just by using simple mean square algorithm. Two algorithms for equalization are proposed in this paper. In algorithm I the receiver does not require to know training sequence in advance. Using algorithm II, the sender does not require to send training sequence either, and data can still be equalized using simple LMS algorithm at low computational complexity.

In this paper a method "Component Series Modeling" (CoSeMod) is presented. This allows fast and easy implementation of scalable model generations for passive component series based on measurement data or specification provided by manufacturer. These can be used in circuit models for fast EMC analysis and optimization, especially in frequency ranges where conducted emission and susceptibility dominate. EMC tasks require high precision equivalent circuit models of components. Models generated with CoSeMod provide in many cases as high a quality as original (static) models do. One feature of scalability is that new netlisting is not needed after component changes. The process of model creation is based on similarities of the components of the same model series (packaging, manufacturing process, material etcetera). Required equations of the relationship between nominal and parasitic values are calculated by nonlinear regression. Model generation for unknown components of a known series is possible with interpolation. Implementation is possible with relatively simple actions made in circuit simulator Saber. An EMC application example of the implemented model is also shown in this paper.

With the development of medical technique and computational electromagnetics, high resolution anatomic human models have already been widely developed and used in computation of electromagnetic fields induced in human body. Although these so called voxel-based human models are powerful tools for research on electromagnetic safety, their unchangeable standing posture makes it impossible to simulate a realistic scenario in which people have a lot of different postures. This paper describes a poser program package which was developed as an improved version of the free-from deformation technique to overcome this problem. It can set rotation angles of different human joints and then deform the original human model to make it have different postures. The original whole-body human model can be deformed smoothly, continuity of internal tissues and organs is maintained and the mass of different tissues and organs can be conserved in a reasonable level. As a typical application of the postured human models, this paper also studies the effect of the step voltage due to a lightning strike on the human body. Two voxel-based human body models with standing and walking posture were developed and integrated into simulation models to compute the current density distribution in the human body shocked by the step voltage. In order to speed up the transient simulation, the reduced c technique was used, leading to a speedup factor of around 20. The error introduced by the reduced c technique is discussed and simulation results are presented in detail.

This paper addresses issues related to the minimization of the computational burden in terms of both memory and speed during the simulation of electrical models. In order to achieve a simple and computational fast model the order reduction of its reducible part is proposed. In this paper the overview of the order reduction algorithms and their application are discussed. MEDEA+/A701 PARACHUTE BMBF/01M 3169 A BMBF/01M 3169 D BMBF/01M 3169 E

This paper presents the results and the limits of 1-D analytical modeling of electrostatic potential in the low-doped p type silicon body of the asymmetric n-channel DG SOI MOSFET, where the contribution to the asymmetry comes only from p- and n-type doping of polysilicon used as the gate electrodes. Solving Poisson's equation with boundary conditions based on the continuity of normal electrical displacement at interfaces and the presence of a minimum electrostatic potential by using the Matlab code we have obtained a minimum potential with a slow variation in the central zone of silicon with the value pinned around 0.46 V, where the applied VGS voltage varies from 0.45 V to 0.95 V. The paper states clearly the validity domain of the analytical solution and the important effect of the localization of the minimum electrostatic potential value on the potential variation at interfaces as a function of the applied VGS voltage.

In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.

This paper analyzes the effect of a change in cell size and of transmit power control on the human exposure to electromagnetic fields. In a simplified network configuration the well accepted COST-Hata model is considered to assess the path loss. It is shown that increasing the base station den- sity will not generally raise the exposure but can rather help to lower it significantly. The exposure due to base stations is hardly affected by allowing a transmit power reduction at the base station for individual links. In contrast to this, it is demonstrated that transmit power control at the mobile sta- tion is a helpful means to lower the exposure efficiently. power control allows the transmission of information dedi- cated to individual users with a power level that is lower than a scheduled maximum transmit power. This results in a re- duction of interference and, furthermore, in a reduction of the human exposure to electromagnetic fields. In this paper the amount of the decrease in the exposure to electromagnetic fields when utilizing transmit power control is quantified. 2 The mobile radio network model To assess the human exposure to electromagnetic fields in a radio network, knowledge of the most important factors in- fluencing the exposure is necessary. Aside from the network layout and wave propagation model, the base station's and mobile station's technical data and configuration are relevant.

This paper deals with optimization of the received power profile for iterative parallel and successive interference cancellation (PIC/SIC) in coded CDMA systems. For practical implementation additional constraints should be applied. This paper focuses on the maximum tolerable bit error rate. It will be shown that optimized power profile can considerably gain the overall system performance. Due to unequal required receive powers an allocation to certain users can be done with respect to their individual power constraints. This is important especially in near-far scenarios. Beside these constraints also the maximum number of iterations is implemented due to limiting the computational complexity in the receiver.

Die Verifikation von digitalen Schaltungen nimmt heutzutage einen bedeutenden Stellenwert ein. In diesem Paper wird ein Weg beschrieben, der die Erstellung und Wartung von funktionalen Testbenches für digitale Designs unterstützt. Für viele Projekte übersteigt der zeitliche Aufwand für das Testen den Aufwand für die Implementierung der Schaltung. In vielen Fällen beträgt der Aufwand für das Testen bereits 70% des Entwicklungsaufwands (Bergeron, 2000). Typischerweise wird die Testbench auch in der gewählten Hardwarebeschreibungssprache (VHDL oder Verilog) implementiert. Diese Sprachen stellen jedoch nicht die beste Wahl für Verifikationsbelange dar. Gründe dafür sind darin zu suchen, dass diese Sprachen wichtige Konzepte aus den Softwaresprachen (wie z.B. Objektorientierung) nicht kennen. Weiters stehen komfortable Softwarebibliotheken (Zufallszahlengenerierung, Stringverarbeitung, etc.) den Hardwaresprachen nicht zur Verfügung. In diesem Paper wird der Einsatz der Programmiersprache Python (PythonHomepage, 2003; Beazley, 2001) für die Verifikation vorgeschlagen, um die benötigte Zeit für die Funktionalen Tests zu reduzieren.

Usually common polarimetric weather radar DSP-products (e.g.: reflectivity, differential reflectivity, linear depolarisation ratio - for both - co-polar and cross-polar signal components) are based on the logarithmic receiver output, because of the large dynamic range provided by the logarithmic receiver. In this paper for the first time we also use the linear receiver output to calculate common weather radar DSP-Products. Using the raw time series radar data recorded with the coherent polarimetric C-band weather radar of the DLR (''Poldirad'', Wessling, Germany) it is possible to do a comparison between processed weather radar echoes from the linear receiver and the logarithmic receiver. After the comparison showed very good results, we continued the work with the linear receiver data, especially on the topic named temporal decorrelation properties of the linear receiver data. This paper includes the first results obtained from two observables that belong to our working topic. The first observable is the ''Time Decorrelation Factor-TDF'' and the second one is the ''Decorrelation Time DTτ''The results have been summarised in the form of empirical relationships, plots and the least mean square (LMS) method of curve fitting was used to give the mathematical relationship for the observables TDF and DTτ. Generally, the paper will also reflect on the statistical properties of radar echoes measured with linear receivers. The usage of the linear receiver data opens a wide field of new applications and products for the work with polarimetric weather radar data, because the linear receiver data also provides phase information which a logarithmic receiver does not.

A functional 10×10 reflectarray antenna is developed for millimeter-waves. It has a gain of approximately 10 dBi and a continuous steering range from −30 to 30∘ in the horizontal plane. In this paper, the entire design process is explained, beginning with the design and function of the antenna element and followed by considerations regarding positioning of the feed antenna. Steering and controlling of the beam are discussed. Finally, the antenna patterns for different steering angles were measured in an anechoic chamber. The design is scalable, built with commercial off-the-shelf components, and the array does not need active cooling.

Radar cross-section measurements require the background reflections to be much lower than the reflections of the device under test. Although, anechoic chambers with special target holders meet this requirement, they are expensive and still have imperfections. To further reduce background reflections or to measure in environments where an anechoic chamber is not suitable, digital signal processing can be used to reduce background reflections. In this paper, a complete signal processing chain realized in Matlab is proposed, involving time gating of the measured target response and a background subtraction technique. Furthermore, the proposed signal processing includes a calibration procedure with either a single known calibration target or multiple known targets to improve measurement uncertainties. A compact measurement setup, consisting of a vector network analyzer and two horn antennas, is used to evaluate the overall performance and the advantages of a multiple known target calibration in a practical manner. The calibrated setup is able to measure the radar cross-section in a frequency range from 2 to 12 GHz with a mean error of less than 0.2 dB for both, VV and HH polarization combinations. It could also be shown, that a multi target calibration can result in an improvement of the measurement uncertainty by about 2.5 %.

Analog computers can be revived as a feasible technology platform for low precision, energy efficient and fast computing. We justify this statement by measuring the performance of a modern analog computer and comparing it with that of traditional digital processors. General statements are made about the solution of ordinary and partial differential equations. Computational fluid dynamics are discussed as an example of large scale scientific computing applications. Several models are proposed which demonstrate the benefits of analog and digital-analog hybrid computing., Comment: 12 pages, 2 figures, accepted paper towards a Special Issue of the open-access journal "Advances in Radio Science"

In order to achieve a safety proof of autonomous driving using simulations, information about the environment has to be determined, which is not sufficiently available until now. This work is concerned with road surfaces and their scattering of radar signals. As it is not enough to look at geometries, as it is already done for many ray tracing approaches, also material and composition have to be investigated. Therefore, measurements are performed using a SAR setup in a laboratory as well as open space measurements using a radar evaluation board on a testing area of the Federal Highway Research Institute. The SAR setup enables a quick estimation on differences in reflection of different test objects. With the result from the latter values for the relative permittivity are calculated for different road surface types exploiting Fresnel's equations. The differences in reflection depending on material and surface structure of the road see in the measurements of both setups are discussed in the paper.

Radar signal processing is a promising tool for vital sign monitoring. For contactless observation of breathing and heart rate a precise measurement of the distance between radar antenna and the patient's skin is required. This results in the need to detect small movements in the range of 0.5 mm and below. Such small changes in distance are hard to be measured with a limited radar bandwidth when relying on the frequency based range detection alone. In order to enhance the relative distance resolution a precise measurement of the observed signal's phase is required. Due to radar reflections from surfaces in close proximity to the main area of interest the desired signal of the radar reflection can get superposed. For superposing signals with little separation in frequency domain the main lobes of their discrete Fourier transform (DFT) merge into a single lobe, so that their peaks cannot be differentiated. This paper evaluates a method for reconstructing the phase and amplitude of such superimposed signals.

Distributed bandpass or band-reject filters generally become larger as the design center frequency decreases. To achieve suitable filters with small dimensions even at center frequencies below 2 GHz, ceramic resonators can be used. These components essentially represent transmission lines with a specified, potentially large permittivity, making them physically short while maintaining a desired electrical length. In this paper, Chebyshev-approximated band-reject filters using capacitors and transmission lines, the latter being represented by ceramic resonators, are investigated. Three filter prototypes are built and their performance is evaluated by measurements. Reasonable bandstop filter properties are found, which are the better the narrower the filter bandwidth is.

According to the recently published IEEE standard 802.15.3d (2017), THz links operating at 300 GHz are viable to achieve more than 100 Gbit s−1 of data rate. This feature can support a transition of the future backhaul connectivity from the underground fibre connection to the wireless, where fibre links are not available or too costly to install. The EU-Japan Horizon 2020 project “ThoR” is working towards the demonstration of such links. A detailed investigation on the influence of weather conditions will help to derive planning guidelines of 300 GHz backhaul links for forthcoming applications. This paper focuses on the dependency of the THz link on the general weather by using ray-tracing simulation. Simulation is conducted combining ITU-R propagation models for atmospheric attenuation (water vapour and oxygen content of air, droplets of rains, liquid content of clouds or fog), a wind-depending swaying model for the antenna poles, and historical measured climate data for the deployment scenarios considered in the ThoR project. As a result, this research will show the feasibility of THz link in outdoor applications under general weather conditions, defines weather-dependent outage probabilities, and allows us to derive planning guidelines of THz links at a frequency of 300 GHz.

This paper treats Characteristic Mode Analyses of three-dimensional test objects in the context of EMC. Based on computed Characteristic Modes and mode-specific physical quantities, series expansions for HIRF- and DCI-induced surface currents are deduced. The contribution of single Characteristic Modes to surface currents at different test frequencies is analyzed. HIRF- and DCI-excitations are compared with regard to their surface current distributions in their resonance region determined by Characteristic Mode Analysis.

Professor Karl Rawer encourages, stimulates researchers. He takes initiative and supports researchers in producing papers about new techniques and methods. As a typical case the authors here report their experience with Professor Rawer during the publication of their papers about a Neural Network approach to model near Earth space processes.

The internally stored electric energy (Q-energy) of a disk monopole antenna increases as compared to a monopole antenna without a top disk. Recently it was shown that the Q-energy can be significantly reduced and the bandwidth increased by shielding the disk monopole antenna using a thin magnetic material. In the present paper we consider the same structure to explain another method to increase the bandwidth by using a shield made of dispersive magnetic material. We apply the Kramers-Kronig transforms to derive physically correct real and imaginary parts of the dispersive magnetic material. We do not aim at a reduction of the internal energy but at a compensation of the electric by a magnetic stored energy for a wide frequency range. Disk monopole antennas with shells consisting of such dispersive permeability are finally numerically evaluated by means of a commercial frequency-domain field simulator.

Wireless energy transfer is often used in industrial applications to power actors or sensors, for example in rotating applications as replacement for mechanical slip rings. In addition to the energy transfer, we have developed inductively coupled data transfer systems to expand the range of possible applications. The data transfer is accomplished by using loosely coupled coils on both sides of the power transfer system. In pure energy transfer systems, resonant coupling is used, meaning that the power transfer coils are both tuned to a common frequency to compensate the relatively small coupling factor between power transmitter and receiver and to achieve an impedance matching between both sides by compensating the inductive component of the transfer coils. In this case, capacitors can be connected in series or in parallel to the coils, leading to a sharp, narrow band resonance peak in the transfer function. In inductively coupled data transfer systems, this approach is often not useful because not just a pure sine wave has to be transferred but more likely a signal of a certain bandwidth. In one of our applications, a 100 Mbit s−1 Ethernet stream is transferred with an occupied bandwidth of 62.5 MHz. The coil structures used so far in our data transfer applications were intrinsically unmatched to the data transfer systems. Additionally, due to the small coupling factor between the data transfer coils, transfer losses in the range of up to 15 dB or worth had to be accepted. This is especially critical regarding the high noise level in vicinity of the energy transfer system and the cross coupling between the two transfer channels. For passive, lossless circuits, Foster's theorem states that the reactance increases monotonically with frequency. Subsequently, the inductive part of a circuit can just be exactly compensated with a capacitance for one single frequency. In contrast, active circuits like a negative impedance converter (NIC) can be used to achieve a non-Foster behaviour, for example a negative inductance can be realized. In theory, an inductance in series or parallel to a negative inductance of the same magnitude would be cancelled out for every frequency applied. For low power level applications like active receiving antennas, this approach has already been successfully used in the past to achieve improved matching of simple antenna structures over a comparably large bandwidth. We make use of non-Foster circuits, namely negative impedance converters, to compensate the inductive part of two loosely coupled inductors to achieve smaller transfer losses and better impedance matching, which should lead to a decreased transfer signal loss and higher signal to noise ratio. The results of this paper serve as a basis for this development. So far, we achieved almost complete cancellation of the reactive part introduced by the loosely coupled data transfer inductors. Unfortunately, the circuits active device used to form the negative impedance converter introduced a highly resistive element, greatly increasing the signal transfer losses. Nevertheless, the theory of loosely coupled inductors is shown in a compact form and a strategy to cancel the reactive part is presented. Simulations and measurements of a transfer system are carried out, both showing good agreement regarding the reactance cancellation. Based on this, optimised implementations will be developed in the future.

Conventional CMOS image sensors with a linear transfer characteristic only have a limited dynamic range (DR) of about 60–70 dB. To extend the dynamic range considerably, the already successfully demonstrated concept of a linear self-reset pixel was employed in this work. With the self-reset concept the limit of the maximum analyzable photo generated charge (Qmax⁡) during the exposure time is extended to a multiple of the saturation charge of the photo diode (Qsat) by asynchronous self-resets of the photo diode. Additionally, the remaining charge at the end of the exposure time is evaluated to increase the resolution of the opto-electronic conversion. Thus we achieved pixels with a DR of more than 120 dB combined with an improved low light sensitivity using a pinned photodiode. This paper focuses on two topics: One is the realization and opto-electronic characterization of further self-reset pixel cells for an experimental optimization of the functionality with respect to linearity and high signal-to-noise ratio. The second one is the assembly and digital readout of a cluster structure composed of 16 × 16 pixel matrix on a CMOS test chip. One constraint for later usage of the pixel cells in a high resolution (> VGA) image sensor is the required layout area of the individual circuit blocks. For the cluster structure a size of 20 × 20 µm2 for the analog part of the pixel containing the photo diode and the other analog circuit blocks, the comparator and the signal shaping, was desired. The circuit design and layout work included several variants of the pinned photo diode with floating diffusion (FD) readout node, which is also used for analog voltage storage, and different control transistors. Further for the comparator a telescopic differential amplifier with high gain was implemented as well as peripheral 10 bit counter/shift register as static and dynamic versions. Test chips have been fabricated in an advanced 0.18 µm CMOS technology for optical sensors with low leakage currents. The sensor chips have been evaluated with a specifically developed test setup which gives the flexibility to arbitrarily generate the digital and analog control signals in terms of timing and voltage levels. Based on this, the number of asynchronous self-resets could be read out from the counters of the pixel cells as coarse values. The remaining charge at the end of the integration time was digitized using a ramp analog to digital conversion and could be read out as fine values. An opto-electronic characterization with adjustable illumination from 0 lx to 13 klx was done to measure and analyze the opto-electronic conversion function (OECF) and the noise of six different self-reset pixel cells having the high-gain differential amplifier as comparator. Finally the coarse values of two implemented 16 × 16 pixel clusters could be read out as a mini camera using a lens for optical image formation.

With increasing radar activities in the automotive, industrial and private sector, there is a need to test radar sensors in their environment. A radar target simulator can help testing radar systems repeatably. In this paper, the authors present a concept of low-cost hardware for radar target simulation. The theoretical foundations are derived and analyzed. An implementation of a demonstrator operating in the 24 GHz ISM band is shown for which the dynamical range simulation was implemented in a FPGA with fast sampling ADCs and DACs. By using a FIR filtering approach a fine discretization of the range could be reached which will furthermore allow an inherent and automatic Doppler simulation by moving the target.

In this paper, we investigate the propagation of high-frequency current waves along a stochastic transmission line inside a rectangular cavity using as basis the model of a transmission line with the symmetry of the resonator. The stochastization of the line is created by a stochastically arranged chain of loads. Using similar models one also can take into account stochastic geometry of the line. Research has shown a significant difference between the propagation of the current wave along the transmission line with stochastic loads in free space and in the resonator. In the first case, the average square of the absolute value of the transmission coefficient exponentially tends to zero with increasing length of the line due to interference phenomena for current waves. In the second case, in the average, the current can penetrate through the stochastic chain of the loads due to the re-reflection of the signal from the walls of the resonator.

This paper summarizes expectations and requirements towards future converged communication systems denoted by 5th Generation (5G). Multiple research and standardization activities globally contribute to the definition and specification of an Information and Communication Technology (ICT) to provide business customers and residential users with both, existing and future upcoming services which demand for higher data rates and granted performance figures in terms of QoS parameters, such as low latency and high reliability. Representative use case families are threefold and represented as enhanced Mobile Broadband (eMBB), massive Internet of Things (mIoT), and Critical Communication, i.e. Ultra-Low Latency (ULL)/Ultra-High Reliability (UHR). To deploy and operate a dedicated network for each service or use case separately would raise the expenses and service costs to an unduly high amount. Instead provision of a commonly shared physical infrastructure offering resources for transport, processing, and storage of data to several separated logical networks (slices) individually managed and configured by potentially multiple service providers is the main concept of this new approach. Beside a multitude of other initiatives the EU-funded 5G NORMA project (5G Novel Radio Multiservice adaptive network Architecture) has developed an architecture which enables not only network programmability (configurability in software), but also network slicing and Multi Tenancy (allowing independent 3rd parties to offer an end-to-end service tailored according to their needs) in a mobile network. Major aspects dealt with here are the selectable support of mobility (on-demand) and service-aware QoE/QoS (Quality of Experience/Service) control. Specifically we will report on the outcome of the analysis of design criteria for Mobility Management schemes and the result of an exemplary application of the modular mobility function to scenarios with variable service requirements (e.g. high-terminal speed vs. on-demand mobility or portability of devices). An efficient sharing of scarce frequency resources in new radio systems demands for tight coordination of orchestration and assignment (scheduling) of resources for the different network slices as per capacity and priority (QoS) demand. Dynamicity aspects in changing algorithms and schemes to manage, configure, and optimize the resources at the radio base stations according to slice specific Service Level Agreements (SLAs) are investigated. It has been shown that architectural issues in terms of hierarchy (centralized vs. distributed) and layering, i.e. separation of control (signaling) and (user) data plane will play an essential role to increase the elasticity of network infrastructures which is in focus of applying SDN (Software Defined Networking) and NFV (Network Function Virtualization) to next generation communication systems. An outlook towards follow-on standardization and open research questions within different SDOs (Standards Defining Organizations) and recently started cooperative projects concludes the contribution.

The wide range of code rates and code block sizes supported by todays wireless communication standards, together with the requirement for a throughput in the order of Gbps, necessitates sophisticated and highly parallel channel decoder architectures. Code rates specified in the LTE standard, which uses Turbo-Codes, range up to r=0.94 to maximize the information throughput by transmitting only a minimum amount of parity information, which negatively impacts the error correcting performance. This especially holds for highly parallel hardware architectures. Therefore, the error correcting performance must be traded-off against the degree of parallel processing. State-of-the-art Turbo-Code decoder hardware architectures are optimized on code block level to alleviate this trade-off. In this paper, we follow a cross-layer approach by combining system level knowledge about the rate-matching and the transport block structure in LTE with the bit-level technique of on-the-fly CRC calculation. Thereby, our proposed Turbo-Code decoder hardware architecture achieves coding gains of 0.4–1.8 dB compared to state-of-the-art accross a wide range of code block sizes. For the fully LTE compatible Turbo-Code decoder, we demonstrate a negligible hardware overhead and a resulting high area and energy efficiency and give post place and route synthesis numbers.

Power semiconductors are used in a growing number of applications. Furthermore, faster switching transients and therefore higher switching frequencies can be realised. This leads to higher radiated interferences at higher frequencies. In power electronic applications, often a cooling concept for the semiconductors is required to comply with the allowed temperature range. Typically, heat sinks are made of aluminium and their conductive behaviour can cause EMC problems. Via capacitive coupling, voltage transients are transferred from the power semiconductor to the heat sink, so that the heat sink behaves as an antenna and radiated interferences occur. Furthermore, a common mode current will appear if the heat sink is grounded. In this paper, a promising approach to reduce radiated interferences from the heat sink and solve the common mode issue by using an electrically isolating ceramic heat sink is presented. The influence of an aluminium nitride ceramic heat sink on cooling performance and EMC behaviour has been investigated. For this purpose, two geometrical identically heat sinks made from aluminium and aluminium nitride have been compared regarding thermal performance and radiated interferences characterised by S-parameters.

Short range inductive data transfer has become very popular in the last years with the increased interest in technologies like RFID and NFC. Additionally, wireless power transfer has been a field of intensive research and product development. In industrial applications, a combination of both is often needed to replace mechanical contacts, mainly for safety and reliability reasons, especially regarding spark prevention and maintenance reduction. In this paper, we present a compact inductive structure that can be implemented in an existing wireless energy transfer system. The structure is developed by field considerations, leading to a single structure comprising two signal ports that are decoupled from each other, but can be used to transfer a signal to a second structure of that kind with very small interference. An optimisation to achieve comparable channel characteristics is conducted by using 3-D field simulations. Subsequent measurements are conducted to verify the achieved performance.

This paper introduces a novel target height estimation approach using a Frequency Modulation Continuous Wave (FMCW) automotive radar. The presented algorithm takes advantage of radar wave multipath propagation to measure the height of objects in the vehicle surroundings. A multipath propagation model is presented first, then a target height is formulated using geometry, based on the presented propagation model. It is then shown from Sensor-Target geometry that height estimation of targets is highly dependent on the radar range resolution, target range and target height. The high resolution algorithm RELAX is discussed and applied to collected raw data to enhance the radar range resolution capability. This enables a more accurate height estimation especially for low targets. Finally, the results of a measurement campaign using corner reflectors at different heights are discussed to show that target heights can be very accurately resolved by the proposed algorithm and that for low targets an average mean height estimation error of 0.03 m has been achieved by the proposed height finding algorithm.

The EMC properties of a cubic metallic shield are highly affected by its resonances. At the resonant frequencies, the shielding effectiveness (SE) collapses, which results in high field strengths inside the cavity. This can cause failure or even breakdown of electronic devices inside the shield. The resonant behaviour is mainly determined by the quality or Q factor of the shield. In this paper, the effects of the aperture size on the Q factor and the SE of an electrically large, cubic shield are analysed. At first, a method is developed in order to determine the Q factor based on the resonance behaviour of the shield in time domain. Only the first resonance of the shield is considered therefore. The results are evaluated for different aperture diameters and compared with theory for the Q factor. The dominant coupling mechanism of electromagnetic energy into the shield is thus identified. Then the effect of aperture size on the SE is analysed. The excitation of resonances is very probable if the interfering signal is an ultrawideband (UWB) pulse, which constitutes a typical intentional electromagnetic interference (IEMI) scenario. Therefore, the relation between aperture size and SE is analysed using the theory of the transient SE for a broadband signal with a constant spectral density distribution. The results show, that a worst case aperture size exists, where the SE has its minimum.

In this paper the equivalent circuit modeling of a nonlinearly loaded loop antenna and its transient responses to HPEM field excitations are investigated. For the circuit modeling the general strategy to characterize the nonlinearly loaded antenna by a linear and a nonlinear circuit part is pursued. The linear circuit part can be determined by standard methods of antenna theory and numerical field computation. The modeling of the nonlinear circuit part requires realistic circuit models of the nonlinear loads that are given by Schottky diodes. Combining both parts, appropriate circuit models are obtained and analyzed by means of a standard SPICE circuit simulator. It is the main result that in this way full-wave simulation results can be reproduced. Furthermore it is clearly seen that the equivalent circuit modeling offers considerable advantages with respect to computation speed and also leads to improved physical insights regarding the coupling between HPEM field excitation and nonlinearly loaded loop antenna.

During the increasing dissemination of renewable energy sources the potential and actual interference effects of wind turbine plants became obvious. Turbines reflect the signals of weather radar and other radar systems. In addition to the static radar echoes, in particular the Doppler echoes are to be mentioned as an undesirable impairment Keränen (2014). As a result, building permit is refused for numerous new wind turbines, as the potential interference can not be reliably predicted. As a contribution to the improvement of this predictability, measurements are planned which aim at the high-frequency characterisation of wind energy installations. In this paper, a cost-effective FMCW radar is presented, which is operated in the same frequency band (C-band) as the weather radars of the German weather service. Here, the focus is on the description of the hardware design including the considerations used for its dimensioning.

The global Digital Elevation Model (DEM) resulting from the TanDEM-X mission provides information about the world topography with outstanding precision. In fact, performance analysis carried out with the already available data have shown that the global product is well within the requirements of 10 m absolute vertical accuracy and 2 m relative vertical accuracy for flat to moderate terrain. The mission's science phase took place from October 2014 to December 2015. During this phase, bistatic acquisitions with across-track separation between the two satellites up to 3.6 km at the equator were commanded. Since the relative vertical accuracy of InSAR derived elevation models is, in principle, inversely proportional to the system baseline, the TanDEM-X science phase opened the doors for the generation of elevation models with improved quality with respect to the standard product. However, the interferometric processing of the large-baseline data is troublesome due to the increased volume decorrelation and very high frequency of the phase variations. Hence, in order to fully profit from the increased baseline, sophisticated algorithms for the interferometric processing, and, in particular, for the phase unwrapping have to be considered. This paper proposes a novel dual-baseline region-growing framework for the phase unwrapping of the large-baseline interferograms. Results from two experiments with data from the TanDEM-X science phase are discussed, corroborating the expected increased level of detail of the large-baseline DEMs.

Continuously increasing requirements for on-board system performances lead to new topologies for the energy distribution in vehicles. One promising concept is the usage of a dual-battery system instead of the conventional lead-acid “starting lightening ignition” battery. As this system is not able to control the current share between the two batteries, its performance depends on the actual battery specific operating points.The initial conditions of state of charge, voltage level and temperature influence the current share and lead to a different voltage drop of the system. This paper yields to, the basic understanding of the current share between the two batteries. The conventional performance estimation method for standalone lead-acid batteries can no longer be applied to this system. Therefore, a new algorithm for the voltage drop calculation of the dual-battery system is proposed. Measurements at different temperatures, states of charge and voltage levels show the system behavior and prove the functionality of the algorithm.

Several immunity test procedures for narrowband radiated electromagnetic energy are available for automotive components. The ISO 11452 series describes the most commonly used test methods. The absorber line shielded enclosure (ALSE) is often considered as the most reliable method. However, testing with the bulk current injection (BCI) can be done with less efforts and is often preferred. As the test setup in both procedures is quite similar, there were several trials for finding appropriate modifications to the BCI in order to increase the matching to the ALSE. However, the lack of knowledge regarding the impedance of the tested component, makes it impossible to find the equivalent current to be injected by the BCI and a good match cannot be achieved. In this paper, three approaches are proposed to estimate the termination impedance indirectly by using different current probes.

Radiated electromagnetic fields from a PCB can be estimated when the source current distribution is known. From a measured near-field distribution, the PCB source current distribution can be found. Accuracy depends on the measurement method and its limitations, the radiation model and the choice of the observation area. Many known methods are based on optimization algorithms for inverse problems that vary a set of elementary radiation sources and create a radiation model. However, apart from the time-consuming optimization process, such methods find one possible solution for a near-field distribution. As this distribution might not reflect the real current distribution, accuracy outside of near-field scan area can be low. Furthermore numerical problems can often be observed. Solving the given inverse problem with a system of linear equations and complex near-field data it can be very sensitive to noise. Regularization methods and an adjusted preconditioning can increase the accuracy. In this paper, an improved radiation model creation approach based on complex near-field data is presented. This approach is based on regularization methods and extended by current estimations from near-field data. Preconditioning is done considering some physical properties of the PCB and its possible current paths. Accuracy and stability of the method are investigated in the presence of noisy data.

The ever increasing use of PEDs (passenger or portable electronic devices) has put pressure on the aircraft industry as well as operators and administrations to reevaluate established restrictions in PED-use on airplanes in the last years. Any electronic device could cause electromagnetic interference to the electronics of the airplane, especially interference at receiving antennas of sensitive wireless navigation and communication (NAV/COM) systems. This paper presents a measurement campaign in an Airbus A320. 69 test passengers were asked to actively use a combination of about 150 electronic devices including many attached cables, preferentially with a high data load on their buses, to provoke maximal emissions. These emissions were analysed within the cabin as well as at the inputs of aircraft receiving antennas outside of the fuselage. The emissions of the electronic devices as well as the background noise are time-variant, so just comparing only one reference and one transmission measurement is not sufficient. Repeated measurements of both cases lead to a more reliable first analysis. Additional measurements of the absolute received power at the antennas of the airplane allow a good estimation of the real interference potential to aircraft NAV/COM systems. Although there were many measured emissions within the cabin, there were no disturbance signals detectable at the aircraft antennas.

Automotive electric components are required to pass radiated emission tests. According to CISPR-25 standard (ALSE method), an expensive anechoic chamber is needed for conducting the field emission testing. Reproducibility due to high sensitivity to chamber and setup details is poor. Alternative methods, which perform measurements without using a chamber are preferred. This paper provides an alternative pre-compliance method for predicting the fields of CISPR-25 results for frequencies below 30 MHz, based mainly on electric near-field measurements. The motivation is that common-mode current measurements or magnetic near-field measurement based methods give good field prediction above 30 MHz, but fail below 30 MHz. The proposed method applies Huygens' Principle for field prediction. The electric field distribution for the defined Huygens' surface and the equivalent currents are estimated from a small number of field measurements close to the ground plane. It is shown that the electric field can be well predicted, compared with a full-wave simulation the deviation is within 4 dB, compared with a standard antenna measurement up to 3 MHz the deviation is less than 1 dB.

The increasing demand for fast wireless communications requires sophisticated baseband signal processing. One of the computational intense tasks here is advanced Forward Error Correction (FEC), especially the decoding. Finding efficient hardware implementations for sophisticated FEC decoding algorithms that fulfill throughput demands under strict implementation constraints is an active research topic due to increasing throughput, low latency, and high energy efficiency requirements. This paper focuses on the interesting class of Polar Codes that are currently a hot topic. We present a modular framework to automatically generate and evaluate a wide range of Polar Code decoders, with emphasis on design space exploration for efficient hardware architectures. To demonstrate the efficiency of our framework a very high throughput Soft Cancellation (SCAN) Polar Code decoder is shown that was automatically generated. This decoder is, to the best of our knowledge, the fastest SCAN Polar Code decoder published so far.

It is well known from classical transmission line theory, that transmission lines can be folded into impedances and thereby used in an electrical network setting. But it is also possible to create large networks of transmission lines consisting of tubes and junctions. The tubes contain the transmission lines and the junctions consider the mutual influences of the adjacent tubes or the terminals. The calculation of the currents and voltages at the junctions can be performed with the help the BLT-equation. So far this method is not applicable for nonuniform transmission lines described in a full wave method, because the lack of a distinct voltage gives no possibility for junctions. Junctions only make sense, when the considered network offers the possibility to propagate a TEM-Mode. If this requirement is fullfilled, nonuniform transmission lines could be included in an electrical network. This approach is validated in this paper in form of numerical simulations as well as measurements.

Model-order reduction provides an efficient way of computing frequency sweeps for finite-element models, because the dimension of the reduced-order system depends on the complexity of the frequency response rather than the size of the original model. For electrically large domains, however, the applicability of such methods is unclear because the system response may be very complicated. This paper provides a numerical study of the effects of bandwidth, electrical size, and scan angle on the size and convergence of the ROM, by considering linear antenna arrays. A mathematical model is proposed and validated against numerical experiments.