This thesis evaluates standard EMC aircraft equipment specifications highlighting their weaknesses and suggesting modifications, some of which have already been included in the new generation of specifications now being introduced. The relationship of the equipment level EMC test to the whole aircraft EMC test is discussed and improvements to this latter activity, which have been developed as a result of the work programme described in this thesis, are presented and evaluated.

Abstract Design and manufacturing techniques of printed circuit boards (PCB's) have advanced from early one or two-layer structures to the multilayer boards where ten or more layers are no longer uncommon. These give additional routing space, potential decrease in device size and various design possibilities like solid ground and power planes. Unfortunately multilayer boards are vulnerable to high coupling between signal vias especially due to PCB resonances. In this study via crosscoupling is investigated on multilayer PCB's. Special attention is given to the coupling due to resonances and vertically aligned blind vias. Problem is approached from the electromagnetic compatibility (EMC) point of view and high accuracy of measurements or models is not the objective. Instead ways to increase isolation are considered important. EMC is considered to include internal functionality of the device. Analytical methods are used to calculate resonant frequencies, fields and quality factors for simple rectangular structures. The PCB cavity is reduced to two-dimensions for numerical calculation of same quantities. Aplac finite-difference time-domain simulator is used to model coupling due to PCB resonances. Isolation between vertically aligned blind vias is estimated analytically. A quasi-static numerical model is used to study a coaxial via structure. Multilayer test boards are constructed for measurement purposes. Simplified resonator structures on two-layer boards are used to test different methods to increase isolation. Measurements show that high coupling between vias may occur due to PCB resonances. This leads to the situation, where previously used isolation methods between vias are not necessarily effective enough. Several means to reduce effects of PCB resonances are described in this study. Measured and modelled results agree well from an EMC point of view. Coupling due to vertically aligned blind vias is also shown to be high. A simple capacitance model may be used to approximate this up to frequencies where the dynamic wave nature of the board starts to be important. From a PCB designer's point of view these results mean that when the board size is not small compared to the wavelength, there is a possibility of resonances and reduction methods have to be taken into account. Also placement of the vias have to be carefully selected especially if blind or buried vias are used.

In general the automotive electromagnetic environment is severe because of the presence of DC motors and ignition. In this thesis, electromagnetic interference and electromagnetic susceptibility are studied. This thesis is divided intro three parts. In Part I we introduce the specification of digital TV (DVB-T) in Taiwan. In Part 2 the reception of digital TV in vehicle and in laboratory is compared. The measurement in vehicle is conducted in order to understand the source of interference and how the disturbance occurs. The standard test in laboratory has to do with the transient susceptibility which is based on ISO 7637. We then analyze the implication of different pulses mandated in ISO 7637. The results are compared with those obtained in vehicular measurement. In Part 3 remedy is proposed to reduce the interference to digital TV.

In this work, based on both experimental and theoretical approach, the contact ESD behavior on a PCB circuit is investigated. The discharge mechanisms of ESD (Electrostatic Discharge) phenomena are discussed by both practical measurement and mathematic analysis. Simplified mathematic models include CR-R¡BCR-C and CR-L are proposed to explain the low frequency phenomena of ESD discharge events. Moreover, some experimental setups with good repeatability are demonstrated for measuring the ESD-induced noise on high-speed PCB and some countermeasures are suggested to reduce ESD damage.

Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 5, 2008) Includes bibliographical references (p. 21-22).

Thesis (Ph. D.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 27, 2009) Includes bibliographical references.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017. / This research project focuses on the implementation of a Reverberation Chamber (RC) by the transformation of an existing electromagnetically shielded room. The reverberation chamber is a kind of shielded room designed to create a statistically random internal electromagnetic environment. The reverberating environment makes it possible to obtain high field strengths from a relatively low input power. The electric fields in the chamber have to be stirred to achieve a statistically uniform field. The first part of this thesis presents an overview of reverberation chamber principles and preliminary calculations are done: the lowest usable frequency is estimated to be close to 300 MHz from empirical criteria. Modelling of the statistical environment is then presented, where electromagnetic quantities are characterised by probability density functions (Gaussian, Rayleigh and exponential); correlation issues are also presented. Measurements are performed in the frequency range of 800 MHz – 4 GHz, dictated by the antennas available for this research study. An investigation of cable losses is conducted, followed by a discussion on measurement accuracy. Mechanical stirrers are designed and manufactured. Electromechanical components are selected based on the literature study. Measurements are obtained through an automated setup using MATLAB®. To verify that the RC, with its in-house designed mechanical stirrers, is well-operated, the stirring ratio is experimentally determined. After this first test, an exhaustive investigation of probability density functions is conducted, taking into account correlation issues. Measurements show that the quality factor of the chamber is close to 2000 at 3 GHz, and that 60 independent stirrer positions at 4 GHz can be used for statistical analyses. Finally, the uniformity test is performed with an improved accuracy using frequency stirring. In conclusion, the CPUT RC passes the validation procedure according to the IEC 61000-4-21 standard by generating the required field uniformity within the accepted uncertainty level.

M.Ing. (Electrical And Electronic Engineering) / In this dissertation, an investigation into reducing Electromagnetic Interference (EMI) through design is presented. Root generation mechanisms of Electromagnetic Interference are often neglected during the design process and later treated symptomatically. Mitigation of Electromagnetic Interference at source often reduces cost and physical size of electronics. This dissertation demonstrates the process and results by which schematic balance mitigates EMI. In addition, the introduction of Geometric Balance and physically designing circuits to be Geometrically Symmetrical are presented and tested to determine whether the design produces mitigating EMI results. Multiple Printed Circuit Boards (PCB’s) were developed and tested against each other to demonstrate schematic balance and other EMI generation mechanisms. The final PCB was designed to be Geometrically Symmetrical and the test results compared. The results illustrate the varying performance of each PCB due to their differing design. The Geometrically Symmetrical PCB presented the best results due to various improvements which include physical layout size and semiconductor placement. An additional important phenomenon discovered was the amount of EMI generated during MOSFET Driver operation. This contributed to a significant amount of EMI during the no-load phase of testing.

D.Ing. (Electrical And Electronic Engineering) / Please refer to full text to view abstract

This thesis analyzes the procedural approach and benefits of applying optimization techniques to the design of a boost power factor correction (PFC) converter with an input electromagnetic interference (EMI) filter at the component level. The analysis is performed based on the particular minimum cost design study of a 1.15 kW unit satisfying a set of specifications. A traditional design methodology is initially analyzed and employed to obtain a first design. A continuous design optimization is then formulated and solved to gain insight into the converter design tradeoffs and particularities. Finally, a discrete optimization approach using a genetic algorithm is defined to develop a completely automated user-friendly software design tool able to provide in a short period of time globally optimum designs of the system for different sets of specifications. The software design tool is then employed to optimize the system design, and the savings with respect to the traditional design methodology are highlighted. The optimization problem formulation in both the continuous and discrete cases is presented in detail. The system design variables, objective function (system component cost) and constraints are identified. The objective function is expressed as a function of the design variables. A computationally efficient and experimentally validated model of the system, including second-order effects, allows the constraint values (also as a function of the design variables) to be obtained. / Master of Science