It is important to investigate the threat posed to commercial aircraft by on board electronic transmitters in the passenger cabin and the cargo holds of large transport aircraft. These transmitters may be in the form of unintentional use of portable electronic devices or even intentional radio frequency (RF) threat sources from terrorists. Thus, it is of interest to determine the "interference path loss" (IPL) from a transmitting device inside the cabin of such aircraft to the antenna terminals of a potential victim system of the aircraft. Past studies have concentrated on measurements. These efforts to measure IPL directly have demonstrated that accurate and repeatible measurements are difficult to obtain. Very little modeling work has been done successfully to understand the IPL on aircraft. In this thesis, we propose a 3-step methodology to quantify the interference path loss (IPL). We then apply this methodology to a broad class of aircraft and show results. To validate our results, we compare our findings to known measurements and discuss possible sources of errors. Finally we suggest areas of improvement to our analysis and propose future work. / Master of Science

Electromagnetic compatibility (EMC) has become increasingly important in present electronic design. Modern high-speed circuitry has earned amplified attention from engineers due to its ability to interfere with neighboring circuitry through electromagnetic interference (EMI). As the operating speed and layout complexity of electronic circuit systems continues to increase, electromagnetic interference (EMI) becomes a serious issue facing circuit designers of the present and future. In this paper, the radiated emissions of a small PCB (including a microprocessor, SRAM, and flash memory) placed within a 1-GHz Crawford TEM (transverse electromagnetic) cell are analyzed. Various programs are executed while the microprocessor runs at different clock speeds. The dissimilarities in the radiated emission spectrums provided by the DUT (device under test) while running various programs at different clock speeds are compared and analyzed. All five programs run by the microprocessor show similar effects when the clock speed is varied. It is demonstrated that when the clock rate of the microprocessor increases, the overall radiation from the system increases. However, varying the software executed by the microprocessor is found to have effects on the emitted radiation pattern. The greatest noise within the radiated emission spectrum is found to come from programs in which the microprocessor communicates with the external SRAM chip. It is also found that the radiation levels for each program executed by the microprocessor change differently as the position of the microprocessor inside the TEM cell is varied. The fast paced lifestyle of modern society has undeniably led to an increase in desire for higher functionality of electronic devices. Whether it is a wireless device, a portable computer, or simply more electronic components inside an automobile, the need for electronics with more capabilities has become a standard in electronic design. However, to increase the function of a digital device, clock frequencies and software have to be altered. It is hoped that this paper will help engineers to take into consideration how changes in clock frequencies and software can affect the radiated EMI within their designs. An engineer's consideration of the effects of EMI within his/her design will help lead to safer, more reliable devices.

Electromagnetic compatibility (EMC), or the field of reducing emissions from and increasing immunity against electromagnetic interference, is an essential part of designing modern electronics. As one would expect, EMC is especially important for things such as aircraft and aviation equipment where outages or disturbances could have severe consequences. The problem presented in this thesis was to consolidate the available legislation regarding EMC for unmanned aircraft and then apply this information onto two commercial systems still under development. Based on the applied rules, pre-compliance measurements were then performed to identify problematic areas of their designs in regards to EMC, or more specifically radiated emissions and electromagnetic immunity. The research process for the legislation involved reading through mainly the official documents and directives published by the European Commission, the European Parliament and the European Aviation Safety Agency (EASA), looking up declarations of conformity made by drone manufacturers and also contacting accredited EMC labs for information on how they usually prove compliance for drones. The conclusion of this research being that (for EMC purposes) drones need to follow either the EMC directive 2014/30/EU, the radio equipment directive 2014/53/EU or the essential requirements of directive 2018/1139/EU depending on the intended usage of the drone and its technical specification. As for application of legislation onto the two commercial systems, because there were no drone-specific EMC standards (i.e voluntary ways to more easily prove conformity) in the EU some simplifications would need to be made. This took the form of applying parts of both the EN 55032 (applicable for multimedia equipment) and EN 301 489-1 (applicable for radio equipment) standards for radiated emissions and immunity testing respectively. While the application of legislation in the end was more simplified than initially planned, the goal of condensing down the available information was still achieved. As for the measurements, it should be noted that while most of the problematic areas that caused the systems to break the limits in the chosen legislation were indeed successfully identified on both systems there are still measurements that should be done in the future. This includes testing conducted emissions and immunity against transient electromagnetic phenomena such as electrostatic discharge (ESD).

M.Ing. / In this investigation charge balancing will be investigated from an Electro-Magnetic- Compatibility perspective. The primary sources of common mode Electro-Magnetic- Interference in switching converters are the switching nodes. This is mainly due to the parasitic capacitance between the switching node and the reference earth. Filtering components that are currently used take up a lot of valuable space resulting in the products overall size and cost to increase. Combating common mode current at the source will drastically reduce the size or the need for these large filters. This investigation will focus on a simple method of reducing common mode noise (produced by the switching node), of a two wire system, at the source by making use of a compensating winding which requires very little or no additional space; a buck converter will be used to illustrate the concept. The investigation will start with an overview of Electro-Magnetic-Interference and its components (common and differential mode noise). This investigation will deal with the measurement of common and differential mode noise as well as general Electro-Magnetic-Interference measurement. A design of the buck converter and its drive circuit will also be presented. Reducing the common mode noise by making use of charge balancing using planar inductors will then be presented. This investigation contains the theoretical analysis as well as experimental results to validate the theory. The experiments show encouraging results in using this technique to minimise common mode noise in switched-mode-power-supplies.

O fenômeno \"crosstalk\" constitui-se de acoplamentos eletromagnéticos não intencionais entre condutores. Motivado pela importância deste fenômeno para a área de Compatibilidade Eletromagnética, este trabalho apresenta uma metodologia de análise do fenômeno através do aplicativo SPICE considerando-se configurações compostas por condutores múltiplos. A proposta de desenvolvimento de uma ferramenta computacional de simulação do fenômeno utilizando uma versão estudantil, com livre acesso, possibilita, entre outras coisas, a disseminação de um modelo alternativo, simples e eficaz, e a inclusão do estudo do \"crosstalk\" no conteúdo programático de cursos de Graduação ou Pós-graduação. Para este fim, adotou-se um modelo de simulação de acoplamento eletromagnético com base em modelos de linha de transmissão. Tal modelo é complementado com geradores vinculados controlados por tensão e corrente, que representam fontes de interferência eletromagnética. Em face de limitações dos blocos funcionais que representam essas fontes no aplicativo, foi utilizado em um primeiro instante um método de representação do modelo através de arquivos-texto, ao invés da utilização da interface gráfica existente no software. Posteriormente, novos blocos foram desenvolvidos e acrescentados à biblioteca, tornando possível à aplicação dessa interface diretamente nas simulações. A validação do modelo foi feita, inicialmente, comparando-se os resultados simulados àqueles disponíveis na literatura internacional. Além disto, foi desenvolvida uma bancada experimental para comprovação dos resultados e validação do modelo implementado no aplicativo SPICE através de casos simples do fenômeno. Esses resultados mostram a viabilidade da utilização dos componentes desenvolvidos para o aplicativo, tornando possível e confiável o uso dessa ferramenta na simulação do fenômeno \"crosstalk\". Passou-se então a aplicação da ferramenta desenvolvida a sistemas mais complexos com um número superior de condutores. / This work presents an approach, in which the well-known SPICE simulator is used as a tool to simulate the phenomenon crosstalk. Basically, it is based on transmission line model, where the electromagnetic interferences are simulated by controlled voltage and current sources. Due to the limitations of the available Spice models concerning multiconductors configurations, additional models were developed and implemented as part of the SPICE library. Theoretical and experimental results were obtained. They were used as part of the validation process of the proposed methodology. The developing of specific models allowed the use of this modeling in SPICE student versions. This turns possible the introduction of crosstalk simulations in undergraduate and graduate courses. Besides, the methodology was applied to complex systems in order to present its versatility.

O presente trabalho apresenta resultados de simulações numéricas de uma célula TEM assimétrica aberta com o objetivo de otimizar seu desempenho. Entre as otimizações, é investigado o uso de fendas resistivas para estender a faixa de frequência de operação da célula. Além disso, otimiza-se o casamento de impedância entre o conector coaxial e a célula TEM. São apresentados os resultados medidos da transição otimizada em laboratório. Foi construída, também, uma célula TEM assimétrica e seu desempenho foi verificado em laboratório, obtendo-se uma perda de retorno maior que 10 dB na faixa de operação (30 MHz a 3 GHz). / This work presents numerical simulations of an open asymmetric TEM cell in order to optimize its performance. Among the optimizations, the use of resistive slots to increase the bandwidth of the TEM cell is investigated. Furthermore, the transition between the coaxial connector and the TEM cell is also optimized. Measurements of this optimized transition were performed in laboratory validating the simulations. A prototype TEM cell was built and its return loss was verified to be above 10 dB over its entire band of operation (30 MHz 3 GHz).

O presente trabalho apresenta resultados de simulações numéricas de uma célula TEM assimétrica aberta com o objetivo de otimizar seu desempenho. Entre as otimizações, é investigado o uso de fendas resistivas para estender a faixa de frequência de operação da célula. Além disso, otimiza-se o casamento de impedância entre o conector coaxial e a célula TEM. São apresentados os resultados medidos da transição otimizada em laboratório. Foi construída, também, uma célula TEM assimétrica e seu desempenho foi verificado em laboratório, obtendo-se uma perda de retorno maior que 10 dB na faixa de operação (30 MHz a 3 GHz). / This work presents numerical simulations of an open asymmetric TEM cell in order to optimize its performance. Among the optimizations, the use of resistive slots to increase the bandwidth of the TEM cell is investigated. Furthermore, the transition between the coaxial connector and the TEM cell is also optimized. Measurements of this optimized transition were performed in laboratory validating the simulations. A prototype TEM cell was built and its return loss was verified to be above 10 dB over its entire band of operation (30 MHz 3 GHz).

Abstract. The problem of Electromagnetic compatibility is a popular topic. It is divided into two categories, one is conducted electromagnetic interference, another is radiated interference. We can use LISN to measure the signal of conducted electromagnetic interference , and use antenna to measure the signal of radiated interference. This paper will focus on the antenna. The frequency range of radiated Electromagnetic Interference measurement is so wide that using the halfwave dipole antenna will be very time-consuming, Therefore broadband antennas are often used in lieu of the halfwave dipole antennas. The design procedure of the log-periodic dipole array antenna is introduced in this article. Simulation data of such antenna using the NEC2 software, including the input impedance and the antenna pattern are also provided. Furthermore, based on the parameters obtained from the simulation, a log-periodic dipole array antenna can be fabricated. In doing so, the simulation results should be modified to take into considerations of the specification of the material used, such as diameters of the materials, and lengths of the transmission lines. Once the construction of the log-periodic dipole array antenna is completes, it can be compared with the simulation results, and the difference between them should be investigated to find out the optimal design parameters. Finally, the antenna factor can be calculated to compare it with the measurement data.

Thesis (MEng(TestandEvaluation))--University of South Australia, 2003.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 24, 2008) Includes bibliographical references (p. 105-106).