Neste trabalho apresentar-se-á um método para a determinação de modelos simplificados de fontes equivalentes de campos elétricos e magnéticos aplicáveis à análise de compatibilidade eletromagnética de sistemas embarcados. Esses modelos são obtidos a partir de medições laboratoriais, com técnicas de cálculos analíticos, numéricos e híbridos. Destacam-se, o fato da utilização do método de medição através de antenas de grandes loops (ou, laços, em português), na determinação de fontes equivalentes de emissão radiada e a aplicação destas na avaliação dos campos eletromagnéticos radiados. A contribuição deste trabalho é a obtenção dessas fontes equivalentes de emissão radiada, que possibilitam a avaliação da contribuição dos campos elétricos e magnéticos em ambientes eletromagnéticos. E também contribui com a aplicação de uma metodologia para a obtenção dos campos elétricos a partir dos campos magnéticos previamente determinados. Em particular, este trabalho pode ser considerado como decorrente da evolução da Dissertação de Mestrado [1]. / It will be shown in this work a method for simplified models determination of equivalent sources for electric and magnetic fields, applicable to embedded systems electromagnetic compatibility analysis. These models are obtained by laboratory tests with analytical calculation techniques associated to numerical and hybrid calculations. This work highlights the application of measurement method by Large Loop Antennas (LLAs) for the creation of radiated emission equivalent sources and the application of a corresponding method for obtaining radiated electromagnetic fields. The contribution of this work is the acquisition of these equivalent sources of radiated emission, which allows the evaluation of the magnetic and electric field contribution in electromagnetic environments. And it also contributes with the application of a methodology to obtain the electric fields from previously determined magnetic fields. In special, this work may be considered as an evolution of the Master\'s Thesis [1]

Este trabalho propõe uma configuração de câmaras excitadas por linhas de transmissão, considerada como potencial solução para as restrições das câmaras reverberantes atuais. Dentre estas restrições menciona-se, por exemplo, as relativas à operação das câmaras em baixas frequências, cujas dimensões poderão representar uma restrição física à sua implementação em ambientes de teste. Outras características físicas podem ser consideradas também restritivas, ao se considerar o volume útil de trabalho e o modo de excitação das câmaras canônicas. Visando satisfazer os índices de mérito aplicáveis, as diversas configurações propostas são avaliadas, onde, além dos arranjos das linhas de transmissão, também são considerados os detalhes relativos às variações da excitação e da carga via controle eletrônico. A metodologia de análise de desempenho da câmara proposta utiliza, basicamente, métodos analíticos, numéricos e avaliações experimentais. A aplicação de algoritmos e métodos de otimização recomendados pela literatura atual e alguns procedimentos desenvolvidos e adaptados pelos autores, foram utilizados na busca de configurações que melhor satisfaçam os índices de mérito adotados. Diversos resultados, obtidos através de simulações numéricas e de avaliações experimentais realizadas em um protótipo são apresentados e comparados, visando uma análise das potencialidades e da aplicabilidade deste tipo de câmara às necessidades dos ensaios de compatibilidade eletromagnética de equipamentos e sistemas elétricos e eletrônicos. / This Thesis presents the proposition of a Transmission Line Excited Chamber configuration. This configuration is considered to be a potential solution for the constraints of reverberation chambers of nowadays. Among this constraints, e.g. the ones related to chamber operation at some MHz, is a physical restriction to implement in tests environments. Moreover the work volume and the canonical chamber excitation ways are also considered restrictions. In order to satisfy the chamber evaluation indexes of merit applicability, several transmission line sets are evaluated, including the details concerned to electronic exciting variation and load variation. The chamber performance analysis methodology is proposed in this work is based on analytical and numerical methods, and also experimental evaluations. Not only optimization algorithms and methods recommended by literature were used in order to reach the adopted indexes of merit but also procedures developed and adapted by the authors. To analyze the chamber capacity to reach all the electromagnetic compatibility test requirements applied to equipments and electric and electronic systems, several tests, were performed over one Transmission Line Excited Chamber prototype. The results obtained by numerical simulations and experimental evaluations are presented and compared.

The Technical Testing and Analysis Center (TTAC) Group at Oak Ridge National Laboratory performs electromagnetic compatibility testing on various radiation detection units. These tests require remote viewing of the equipment’s display to monitor its compliance with national and international standards. The Commercial-Off-the-Shelf (COTS) camera equipment that is used to monitor the displays exhibits radio frequency susceptibilities causing issues when determining the actual susceptibilities of the device under test. In order to mitigate this issue, a COTS camera was placed in two common test positions and cycled through three angled orientations with various radio frequency shielding methods applied. The development of these shielding methods was investigated in this thesis. The goal was to reduce the number of susceptible frequencies. The reduction of susceptibilities would greatly increase the viewing capacity of the cameras during testing. The techniques discovered have allowed for other COTS camera equipment to be modified and used effectively during electromagnetic compatibility testing.

Modern gridded ion thrusters for CubeSats operate by generating high power and canpose challenging problems with Electromagnetic Interference (EMI). In order to verifycompatibility with neighbouring equipment, strict standards such as the militarystandard MIL-STD-461G, are required to be followed to achieve ElectromagneticCompatibility (EMC). To avoid abrupt and cataclysmic delays in production time, incase the product fails to comply with the requirements, companies integrate in-housepre-compliance tests into their development phase. The objective is to implementin-house measurement methods on an electric propulsion model NPT30 developedby ThrustMe. This document explains the process and methods to perform conductedemission test on power lines and radiated emission tests in the magneticfield. A custom measurement system integrity verification was developed for theradiated emission test. The presented results provide the engineers at ThrustMe aninsight on the electromagnetic behaviour on the ion thruster NPT30 and whethermodifications need to be included in the next development iteration to mitigate forthe detected excessive emission levels. When EMC methods are implemented earlyon in the development process, there are more pre-emptive mitigation options withless costs in time and money. By performing in-house pre-compliance tests andtaking measures to prepare for the tests at a certified EMC test house, the companycan be more confident in their product at passing the EMC tests. Based on the twoperformed in-house tests, the engineers at ThrustMe began to include mitigationmethods in the following circuit design iterations.

Electromagnetic compatibility remains an important topic in the design and manufacturing of printed circuit boards (PCBs). Compatibility of these devices with their surroundings is becoming increasingly difficult as a modern PCB can have hundreds or thousands of parts, operating on many layers, and all at high speed. One such part is a via and its clearance, or via hole, commonly required in multilayer circuits where vertical connections between layers are used. The via hole may be exposed to large electromagnetic fields within the PCB. Although electrically small, the via hole provides a pathway for the fields to excite the exterior, either directly or through coupling to adjacent structures. To quantify this process, the near fields and radiation of an excited via hole are analysed, and are the focus of this thesis. The near fields of the via hole are first decoupled into electric and magnetic fields of the 'static' type. In both cases a series solution for two regions, one outside, and one inside the layers is constructed. The coefficients of the terms of the series are chosen to best satisfy the boundary behaviour of the fields on the conducting surfaces and across the hole. The criteria for assessing quality of the solution is based on the least squares method (LSM). Linear equation systems for both models are derived, and as no numerical integration or discretisation is required, an efficient and robust implementation to find the near fields is developed. Transformation into the far field is then achieved through surface integration of relevant field quantities close to the via hole. The far fields are best viewed as that due to two dipoles, of the magnetic and electric type, with strength and orientation depending on how the via hole is excited. It is shown that the two dipole model is sufficient to find the radiation from a 1mm diameter via hole at a frequency up to 8 GHz. Of further interest is how the choice of via hole dimensions affects the dipole moments and the near fields solved earlier are a key to this understanding.

This PhD thesis addresses the threat posed to society by sources that can produce high power electromagnetic pulses (HEPM) and be used maliciously to disturb or damage electronic equipment. The vulnerability from intentional electromagnetic interference (IEMI) has increased in the recent decades due to the widespread dependence of the civil society on sensitive electronic systems and proliferation of radiation sources. As the characteristics of the disturbances associated with IEMI often have very high frequency content, the existing mitigation measures and protection components may not be adequate. It was seen that for ultra wideband (UWB) transients low voltage protection components may not work as intended, due to parasitic components that arises from the packaging of the device. The large spatial distribution of many civilian facilities and critical infra-structures (e.g., power generation, communications, train system, etc.) presents many unexpected ports for an attacker as the majority of the parts of these systems are not protected or secure. As the new European Rail Traffic Management System (ERTMS) will utilize wireless communication for communication and control of the trains the vulnerability from different radiating HPEM sources was investigated. Angles of incidence and frequencies that are a threat in a given situation are identified. Due to the possibility of unexpected ports, the propagation of differential mode ultra wideband transients in low voltage power networks, when injected into a power socket of a facility, was studied. The effects on the transient propagation from cable bends, switches and junctions were studied, both in a laboratory setup and in the network of a facility. Also, as modern electronic equipment and systems may not be tested for waveforms and disturbances other than standardized EMC tests, experiments on some common commercial-off-the-shelf (COTS) equipment were performed with non-standard test situation. It was seen that these could easily be disturbed or even permanently damaged. In addition, due to the inherent difficulties with IEMI, a new method for classifying facilities from IEMI is suggested. It is based on available terminology of accessibility (A), susceptibility (S) and consequence (C), but expands these and forms the so called IEMI/ASC-cube.

ElectroMagnetic Interferences (EMI) are emerging problems in today's high speed circuits. There are several examples that these interferences affected the circuits and systems. This work tries to reduce the abovementioned problems in synchronous systems by modifying the clock signal such that it produces less interferers. In this thesis first EMI and its sources and related definitions are studied in Chap.1 and then a theoretical background is presented in Chap.2, finally Chap.3 and Chap.4 are dedicated to circuit implementation and simulation results, respectively. A novel multi-segment clocking scheme is presented in this thesis. An analytical methods for formal verification of advantages of this clocking method is presented in Chap.2. Chap.3 and Chap.4 also are devoted to implementation, simulation and comparison of proposed clocking method versus other methods. Since proposed clocking method does not set any constraint on timing (speed of the circuit) and does not impose very high extra power consumption on the circuit, compared to the conventional clocking, this method could be used to reduce interferences in system.

According to the regulation announced by Bureau of Standard, Metrology & Inspection (BSMI) of Ministry of Economic Affairs (MOEA), lamp fixtures must follow safety and electromagnetic compatibility (EMC) standards. However, the self-ballasted fluorescent lamps in the fixture should only be approved by the safety test but not regulated by EMC standard. Obviously, fixtures without light bulbs do not generate any electromagnetic noise. Electromagnetic interference (EMI) comes from the fluorescent light bulb embedded with an electronic ballast which included an inverter with high-frequency switching. A variety of tests demonstrate evidently that a fixture with different self-ballasted compact fluorescent lamps may possibly violate the EMC standard, revealing the absurdity of the regulation. In fact, self-ballasted fluorescent lamps use mostly self-excited electronic ballasts. The operating frequencies for this kind of electronic ballasts can not be precisely controlled due to the influence of many factors. They are not operated at a specified frequency but in a frequency range. This means that the generated EMI spectrum is hardly predicted, especially when a fixture is fitted by light bulbs from several manufacturers. This research inducts the worst cases from numerous measurements on a fixture with 1 piece to 8 pieces of light bulbs, and then attempts to design an EMI filter for all cases. As a result, a lamp fixture with the filter at the line input terminal can suppress the EMI. As long as the consumer buys the lamp fixture which are installed with the EMI filter together with any bulb in use, EMI noise can comply with standard limits.

Die Elektromagnetische Verträglichkeit (EMV) betrachtet die Fähigkeit eines elektrischen Gerätes, in seiner elektromagnetischen Umgebung störungsfrei zu funktionieren, ohne diese dabei unzulässig zu stören. Zur Prüfung der Elektromagnetischen Verträglichkeit werden verschiedene Messumgebungen verwendet. Die Messung der strahlungsgebundenen Störfestigkeit und Störaussendung kann zum Beispiel in einer Modenverwirbelungskammer (MVK) erfolgen. Bei der Störfestigkeitsmessung wird der Prüfling einem externen Prüffeld ausgesetzt und untersucht, ob dieser die definierten Kriterien für einen störungsfreien Betrieb erfüllt. Für das Prüffeld muss vor der Messung nachgewiesen werden, dass die Anforderungen an dessen Homogenität eingehalten werden. Einen entscheidenden Einfluss auf die Homogenität des Prüffeldes hat der sogenannte Rührer. Bei einer MVK handelt es sich prinzipiell um einen Hohlraumresonator, in den ein mechanischer Rührer, d.h. ein elektrisch großer, drehbarer Streukörper integriert wird. Durch die Drehung des Rührers verändert sich die Feldverteilung in der MVK, was auch als Verwirbelung bezeichnet wird. Prinzipiell ergibt sich für jede Stellung des Rührers ein inhomogenes Feld mit lokalen Minima und Maxima. Ein Ziel bei der Verwendung von Modenverwirbelungskammern ist es, mit Hilfe geeigneter Verfahren Rührerstellungen zu finden, deren Feldverteilungen in Überlagerung ein möglichst homogenes Prüffeld erzeugen. Zum Lehrstuhl für Theoretische Elektrotechnik und Elektromagnetische Verträglichkeit der Technischen Universität Dresden gehört seit 2010 eine Modenverwirbelungskammer. Die Charakterisierung dieser MVK sowie eine weiterführende Untersuchung zur Wahl der Rührerstellungen bilden die Schwerpunkte der vorliegenden Arbeit. / In 2010 the Chair of Electromagnetic Theory and Compatibility of Technical University Dresden could extend its laboratories by a reverberation chamber with the dimensions 5.3 m, 3.7m and 3.0 m. Since then, a detailed characterisation of the chamber as well as further investigations have been the main emphasis of the authors research. The submitted doctoral thesis presents the obtained results. With the design, the fundamentals of operation and further characterisation of the reverberation chamber, given in Chapter 1 and 2, it aims to give an introduction and better understanding of reverberation chambers. On this basis, the authors research focused on methods for determining the independent stirrer positions in reverberations chambers. The results of the investigations are presented and summarised in chapter 3. One scope of Electromagnetic Compatibility are radiated immunity measurements. Besides the GTEM cell and the anechoic chamber the reverberation chamber gains in importance as an alternative measurement environment. A reverberation chamber is a shielded room with reflecting walls and one or more integrated mechanical stirrers. By rotating the stirrer the spatial boundary conditions for the electromagnetic field quantities are altered. The resulting change of the spatial field distribution depends on the location within the chamber and the geometry of the stirrer. Each stirrer position yields an inhomogeneous field distribution created by interfering waves. A general aim is to find a set of stirrer positions, whose superimposed field distributions create a more uniform test field. In practice, the given requirements for the homogeneity of the test field shall, with regards to an optimisation of measurement time, be realized with a minimum number of stirrer positions. In this context the term ’independent stirrer positions’ was established and describes stirrer positions, whose field distributions are linearly uncorrelated and therefore assumed to be practical for creating a more homogeneous test field using only a minimal number of stirrer positions. A general method for determining the number of independent stirrer positions in reverberation chambers is presented. The method uses a certain number of measurement positions in a defined test volume in order to characterize the spatial field distribution inside the chamber. Using the Pearson correlation coefficient the field distributions of the stirrer positions are tested for linear correlation and pairs of independent stirrer positions are determined. On this basis, cliques of pairwise independent stirrer positions are identified using appropriate algorithms. It is shown that the general method yields detailed information about the number and distribution of the independent stirrer positions and is therefore particularly suitable to evaluate other methods. Finally, the standard method according to IEC 61000-4-21 as well as selected alternative methods, that have been proposed in the past, are evaluated and compared based on the results of the general method.

Electromagnetic compatibility (EMC) standards for an accredited test laboratory require that the measurement uncertainty of the measuring instruments be characterized. The CISPR 16-4 standard gives guidance to the magnitude of this uncertainty, but no method of characterization. This thesis describes a method to perform this characterization on a conducted emissions measurement system, taking advantage of full system analysis techniques to reduce the uncertainty to exceptionally low levels. In addition, a framework is introduced whereby uncertainty can decomposed into its constituent parts such that the laboratory operator can identify methods to improve the systems performance.