In areas suitable for wind turbines, compatibility with nearby radar systems must be assessed to determine whether the target coordinates could be unduly restricted. A new method, based on complementary measurements and electromagnetic simulations, uses existing reference reflectors to generate a field strength distribution in these areas. This distribution is then used to simulate the impact of new wind turbines on the terrain. The method is tested in the vicinity of a monostatic long-range 3D radar in L-band, where there are many existing obstacles on the ground, including wind turbines. Measurements are performed using an additional device that runs in parallel to the regular signal processing and records intermediate frequency (IF) signals from the receiver. In a site-specific scenario, radar return over the terrain is measured and compared with state-of-the-art simulations. A validated incident field in areas of interest is then used to estimate additional effects caused by new wind turbines to be planned. The deflected effective antenna diagram behind obstacles like wind turbines is shown with potential impact of terrain.

This paper presents a project-based learning (PBL) approach to provide students with an in-depth understanding of the concept of capacitive coupling. Capacitive coupling, among other coupling mechanisms, is of fundamental importance in the analysis of electromagnetic interference (EMI) problems and thus part of electromagnetic compatibility (EMC). It is fundamentally based on the interaction of three-dimensionally distributed alternating electric fields between several conductive structures. For simple geometries, it can be described by integrated quantities voltage, charge and capacitance and be modeled using equivalent circuit diagrams. For complex geometries, numerical simulation tools are typically used. In the project idea presented here, the spatial field distribution is firstly calculated and visualized using 3D EM simulation software. Parametric simulations are then used to develop discrete equivalent circuits that describe the behavior in a simplified way using the integral variables described above. An analytical description based on geometry and material data is compared with the numerical results. Finally, the simulated structure is built by students as a real structure and measured using a vector network analyzer (VNA). The students can compare and validate their results with the data they have collected themselves.Over the course of a semester, students work on this project, which deals with the above-mentioned research topic. They use different methods and learn to compare and evaluate their results. In this way, students develop a deeper understanding of the content as well as critical thinking, collaboration, creativity and communication skills. PBL can thus unleash a stimulating, creative energy in both students and teachers.

This work describes the implementation of an FPGA-based teaching and research platform for university education of electric engineers. The aim is to provide students with practical experience in design and implementation of control systems, particularly with regard to electromagnetic compatibility (EMC). The platform enables students to implement different control strategies and investigate their effects. The importance of FPGAs for real-time applications is explained and initial measurement results are presented. As a result, this platform offers an effective opportunity to experience and deepen the interaction between the various engineering disciplines.

This work is using a new method allowing to identify reflecting objects in the surrounding area of Doppler VHF Omnidirectional Radio-range (DVOR) transmitters. It is based on a bi-static, partially cooperative Radar application. Here, this method is applied – using received signal power measurements – to derive a quantitative value of an equivalent radar cross section (RCS) of wind turbines. The analysis is focussed on wind turbines in a distance of 5 to 12 km around a DVOR transmitter in Hehlingen, Germany.

Doppler VOR (D-VOR) transmitters are used as navigation aids in aviation. They transmit an omnidirectional phase reference in an amplitude-modulated (AM) sideband and directional phase information on a frequency-modulated (FM) subcarrier. In an airborne D-VOR navigation receiver, a directional information (azimuth angle) related to the position of the aircraft and the location of the transmitter can be derived from the difference of these two phase signals. In this work, the accuracy of AM and FM phase signals is firstly investigated analytically and afterwards verified by measurements. It will be shown that in established procedures, phase inaccuracy is dominated by the AM signal, since the FM signal is about 21 dB less noisy. Subsequently, a novel method is presented that improves the accuracy of the azimuth angle by orders of magnitude in case of D-VOR transmitters. This new method inherently reduces noise of the AM phase and thus yields a significant increase in accuracy. As a result, the remaining FM phase uncertainty becomes dominant for the total uncertainty of the bearing indication. Finally, the application of the new method to real measured signals confirms the theoretical expectations.

This dataset provides digital IQ baseband data, IMU and GPS time stamps for an orbital flight around Bremen Doppler VOR. The data was recorded on July, 13th 2020.

A Doppler VHF Omnidirectional Radio range (DVOR) radiates an omnidirectional signal that is used to generate a ground clutter map of reflective objects in this Passive Bistatic Radar (PBR) application. The derivation of the clutter map and its RCS values are discussed in this paper. The data are finally used as preload parameters to forecast the degradation of the VOR angular bearing when used for aircraft navigation. A small aircraft carrying a VHF sensor performs an orbit flight around the transmitter. Two signal properties are analyzed: Doppler shifts from the direct to the scattered signal deliver the difference of incident angles for all scatterers. Secondly, the DVOR inherently transmits a signal that has a directional-sensitive frequency modulation component which means that the PBR transmitter is partially cooperative. A Matched Filter is used to derive that directional information from the same scatterers, which then allows their localization by means of a cross bearing. Since the system is strictly linear, specific RCS values can be assigned to reflective objects on ground.

An experimental DC-DC buck converter architecture is presented that allows on-line optimisation of conducted emissions. It is based on a micro-controller allowing a very flexible implementation of the voltage controller itself and simultaneously to run an embedded optimisation algorithm in order to find best parameter sets for spread spectrum pulse width modulation methods. In addition to minimising EMI noise, further quality targets, e.g. load or line regulation can also be optimised. The embedded design makes it attractive for modern Artificial Intelligence (AI) strategies which need a huge number of parameter evaluations.

The one-antenna method is adopted to the practical antenna validation needs in EMC laboratories. The proposed setup allows verification of important characteristics like antenna gain and antenna factor on a regular basis. The experiments show very good agreement with manufacturer calibration data. For frequency bands above 1 GHz the metallic wall of a typical shielded room can be used to calibrate e.g. wide band horn antennas. Considerations about potential sources of measurement errors are investigated, while the application of equi-ripple FIR filters - applied during the time domain gating - allows to minimize the uncertainty.

In this contribution the authors summarize some aspects of electromagnetic field theory related to studies of electromagnetic compatibility and propose how they can be introduced in lectures in an attractive and interactive way. Simple examples with practical relevance are discussed that can serve as a motivation for students. In fact, presented fundamental field theory aspects for example with respect to the shielding of fields are commonly mistaken even at industrial working levels, so it is reasonable to anticipate this in EMC lectures.

The radar echo of a large wind turbine (WT) is investigated in the C band: An unmanned aerial system (UAS) is used to perform a reflectivity measurement across the flight altitude using a passive bistatic radar (PBR) constellation of a non-cooperative precipitation radar transmitter in horizontal polarization. This is done at various distances to check if far field conditions apply to derive a radar cross section (RCS). As a fully independent method, a monostatic FMCW radar is installed on ground at certain distances to the WT. The results of both methods are compared against each other regarding the applicability of the RCS.

Signal integrity is of high importance to highspeed digital interfaces and is typically analysed in the time domain using eye-diagrams. The available data of devices under investigation are often given as S-Parameters in the frequency domain and hence have to be transformed into the time domain. Here, problems like passivity and causality might occur. Using a SPICE circuit model with only passive components avoids these problems. In this work, such a model is designed by an expert based on knowledge about the physics. Subsequently, component values of this SPICE model have to be tuned to match the given data in the frequency domain. Even for small networks the design space is too large for exhaustive search. Here, a novel computational optimisation algorithm is proposed and used for the automated tuning. An advantage of this new method is that no control parameters have to be tuned for the optimisation itself. Another advantage is that the algorithm can be parallelised and hence benefits from multi-core architectures of modern workstations. The method was applied to the modelling of a planar coil. It was shown that the algorithm is capable of finding near-optimum solutions within reasonable time, satisfying requirements for practical applications.

Previously, a variation of Asynchronous Population Based. Hill Climbing was applied to a discrete optimisation task from the field of electronic circuit design with a challenging 9 dimensional search space. The algorithm exhibited a certain behaviour, which is analysed in this new research. A problem was the asynchronous nature of the search algorithm, which did not allow the search threads to save the internal state data into log files. Instead, a novel monitoring strategy had to be developed, which accesses this internal data via shared memory in specified times intervals. It was possible to show that the algorithm under investigation is capable of switching between exploration and exploitation of the search space during the search. This prevents the algorithm from being stuck in a local optimum.

This paper presents the stepwise SPICE model generation for Transient Voltage Suppression (TVS) diodes allowing to represent the 2nd and 3rd harmonic distortion behavior in circuit based simulations. The model is based on semiconductor physics and generated using measurement data of the device. The generation of this model is based on the I/V characteristics, the behavior of the capacitance versus diode voltage variations, and tuning at one single input power level at the fundamental frequency as well as for the 2nd and 3rd harmonics. The simulation tool used for the device modelling is Keysight Avanced Design System (ADS).

This work presents a design combining an electromagnetic bandgap structure with periodically shaped differential signal lines for the suppression of common mode noise. This hybrid design is compared against two individual layout structures and a regular reference line. Besides the common mode rejection also the mode conversion is considered.

The long term goal of this research is to develop a swarm of autonomous underwater vehicles (AUVs), which can be used to locate submarine sources of interest, like dumped radioactive waste or ammunition. The overall search strategy of the swarm is based on particle swarm optimisation (PSO). Standard PSO relies on correct localisation and timely communication in order to be able to converge towards the global optimum. However, underwater communication is slow and unreliable and the exact localisation of an AUV is difficult. Therefore, this paper presents an empirical study of the effect of communication and localisation error on the convergence capabilities of PSO. A simulation based on cellular automata is presented and a model of communication and localisation error is incorporated into the PSO. It is shown that both types of errors have a negative effect on the performance of the search, with localisation error having the greater contribution.

In portable electronic devices, like smart phones, coupled planar coils are often used as common mode filters (CMF). The purpose of these CMF is to suppress electromagnetic interference (EMI) between wireless communications systems (e.g. WIFI) and digital highspeed interfaces (e.g. USB 3). A designer of such an electronic device usually carries out a signal integrity (SI) analysis, using models of the system components. There are two alternative ways of modelling the CMF: One is based on matrices (called S-parameters) that describe the behaviour in the frequency domain and are either derived from measurements or simulation tools. The other is using a representation based on lumped circuit networks. In this work, a lumped network is generated manually based on expert knowledge. The advantage of this approach is the reduced number of only passive network components compared to traditional methods that produce much larger networks comprising of many active and passive devices. On the other hand, suitable component values of the lumped network need to be found so that the network exhibits the same frequency response as the physical device. Since there are many interacting parameters to be tuned, this cannot be achieved manually. Hence, a genetic algorithm is applied to this optimisation problem. Two sets of experiments were carried out and a sensitivity analysis has been conducted. It has been shown that the proposed method is capable of finding near optimal solutions within reasonable computation time. INTRODUCTION Modern portable electronic devices have to be as compact as possible whilst being efficient. In such devices, miniaturized planar coils can be found, for example, in common mode filters which are built directly into integrated circuits. For the design of these coils, sophisticated simulation tools based on the method of moments (Keysight, 2016; Harrington, 1968) are often used. Usually, these simulations return frequency dependent scattering parameters (S-parameters, (Pozar, 2012)). This is a black-box approach describing the electrical behaviour in the frequency domain at the ports (or: terminals) of the device without revealing details about the physics of the internal structure (1). [S] =  Sdd,11 Sdd,12 Sdc,11 Sdc,12 Sdd,21 Sdd,22 Sdc,21 Sdc,22 Scd,11 Scd,12 Scc,11 Scc,12 Scd,21 Scd,22 Scc,21 Scc,22  (1) In matrix (1) all elements are complex valued and frequency dependent. The two parameters Sdd,21 and Scc,21 describe the transmission characteristics between the two ports for two different modes of operation, differential mode (dd) and common mode (cc). Those parameters with mixed indices (Sdc,ij and Scd,ij) are relevant for the conversion from one mode to another; for that reason the elements of matrix (1) are also called mixed-mode S-parameters (Bockelman and Eisenstadt, 1995). For passive and reciprocal devices the forward and reverse transmission parameters Sx,21 and Sx,12 are identical. The focus in this work is on Sdd,21 and Scc,21, which are the most important parameters for real world applications. Fig. 1 shows the two modes of operation for a twoport device, like a CMF. The two ports are denoted by the indices 1 and 2 as used in (1). In differential mode (Fig. 1 a)) opposing currents (I+, I−) are applied to the pins of port 1. There is no current in the ground path (Ignd = 0). The transfer characteristics of this mode from port 1 to port 2 is described by Sdd,21. In common mode (Fig. 1 b)), the pins of port 1 are driven commonly, resulting in a return current of the same amplitude in the ground path. The transfer characteristics of this mode from port 1 to port 2 is described by Scc,21. However, sometimes a designer needs to analyse the behaviour in the time domain as well. Here, an equivalent circuit model is usually required, which exhibits the Proceedings 31st European Conference on Modelling and Simulation ©ECMS Zita Zoltay Paprika, Péter Horák, Kata Váradi, Péter Tamás Zwierczyk, Ágnes Vidovics-Dancs, János Péter Rádics (Editors) ISBN: 978-0-9932440-4-9/ ISBN: 978-0-9932440-5-6 (CD)

The interference of Doppler echoes caused by rotating wind turbines is a major concern for meteorological institutes in the proper operation of weather radar stations. While research is ongoing to characterise this interference by means of simulation or measured data of pulsed radar system, this paper addresses measurements with FMCW signals. Most weather radar stations are operated in the C-Band (5.6 GHz). For the characterisation of wind turbines, a portable, flexible and economic design of an bi-static FMCW radar is presented. Initial measurements show adequate spatial resolution and sensitivity. The architecture is using IQ-mixing allowing complex signal processing of the baseband signal.

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.

In order to utilise the computing power offered by modern multi-core computer systems, APBHC, a new parallel search algorithm is proposed in this paper. This algorithm uses a number of parallel, asynchronous threads, each performing hill climbing independently of each other whilst sharing information about the best solution found so far amongst all threads. This information is used to adapt the maximum step size during the search. One advantage of this approach is that this new algorithm has no control parameters, which would require tuning. The other advantage is that it can make use of all processing cores available in a computer system. The new method was applied to the problem of Spice Model Generation. It was shown that it out-performs Genetic Algorithms (GA), which were applied to this problem in the past, without the need of time consuming parameter tuning.