Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [192]-207).

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (p. [125]-135).

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (p. [130]-147).

Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Guest, Peter S. ; Goroch, Andreas K. "March 2010." Author(s) subject terms: Electromagnetic propagation, electromagnetic scattering, groundwave propagation, mathematical techniques, variance reduction. Includes bibliographical references (p. 67-68). Also available in print.

Thesis (M.S.)--Duquesne University, 2009. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p. 56-58) and index.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 199-205).

To design high frequency complex electromagnetic structures with TLM is not trivial in spite of the simplicity of the fundamental TLM algorithm. This is because TLM is a time and space discretization method in which the entire computational domain must be filled with nodes. In three-dimensional cases, the computational effort to solve realistic problems would soon become intractable unless special techniques are used. To be attractive to the design engineer, field simulation tools must include these advanced techniques automatically in the models. New TLM features and computational techniques have been developed in this thesis to overcome the above mentioned problems. An experimental multi-purpose electromagnetic field simulation tool has also been created to demonstrate the features and techniques developed in this thesis can be easily integrated into a well designed tool. / Graduate

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.

D.Ing. / The necessity of frequency selective interconnects in future integrated power electronic systems are highlighted. A brief historical background illustrates that such interconnects have been utilized successfully in other fields of electrical engineering, although based on different high frequency effects, and configurations. Based on high frequency characteristics of typical interconnects, it is hypothesized that the required frequency selectivity could be obtained through utilization of the skin- and proximity effect, and low conductivity materials, to increase high frequency resistance significantly. Finite element simulation results for a large number of interconnects, and reference structures, are presented in an effort to identify relevant parameters and mechanisms. A hybrid lumped / distributed parameter impedance model is proposed. Parametric analysis is conducted to determine limitations and constraints of the proposed technique. Frequency selective damping of turn-off related power electronic switch and interconnect inductance resonance, is investigated as a possible application of such higher resistance. A simplified analytical model is proposed, and utilized to calculate turn-off waveforms and percentages of damping. An approximation of maximum damping possible is presented. Utilization of enhanced high frequency resistance to realize interconnect based low pass filters for medium power integrated power electronic modules, is investigated as a second application. Based on typical parameter influence, a number of structures are evaluated with finite element simulations. An analytical, lossy transmission line model is developed. Parametric analysis for a chosen structure is conducted, followed by discussion of maximum attenuation, and relative effectiveness. As a third application, the above concepts are applied to 1.5kA nominal current interconnects. A number of structures are evaluated. Application of consecutive impedance mismatches to increase attenuation is investigated. Current and voltage capacity constraints are discussed. Experimental verification of the presented concepts in general, are presented. Technical difficulties and limitations are identified. An objective oriented discussion completes the thesis, with the conclusion that the original hypothesis has been validated.

Scientific views on EMF radiation dosimetry and models increasingly suggest that even a tiny increase in the incidence of diseases resulting from exposure to EMF radiation could have broad¹ implications for public health, social accounting and the economy. In South Africa (SA) there is no national EMF radiation exposure protection standard, statutory monitoring or regulations. Multinational High Court deliberations indicate the need for public interest EMF radiation exposure protection standards in South Africa. Domestic citizens, academics, as well as regulatory and legislative practitioners, are unable to effectively monitor and investigate EMF radiation exposure emissions from infrastructure sources, because industries refuse to provide the required data. Industries have, since 2003, continually obstructed access to the data and the establishment of a national EMF radiation standard, citing that it would be in conflict with their strategic economic interests. The demonstration of a public interest override (PIO) function is legislatively required to gain access to the required data. This study constructed (1) a framework and (2) a model to perform test simulations against the (3) PIO criteria to demonstrate a PIO function and tested one PIO simulation scenario. Testing the PIO scenario firstly required the construction of a public interest framework, drawing input from multiple disciplines. The framework literature review used systematic case law and scientific-technical analysis whilst the framework science sought to understand the connections, feedbacks, and trajectories that occur as a result of natural and human system processes and exchanges. The EMF radiation exposure system functions to support human wellbeing needs and to explore the benefits and losses associated with alternative futures with the goal to uncover the current and future limits thereof. In the second instance a HYGEIA² model was selected as a base investigation and forecast simulation tool. The study had to uncover the key attributes and parameters necessary to construct and to run successful EMF radiation exposure simulations. Thereafter the HYGEIA model was modified to specifically identify and evaluate EMF radiation exposure hazard conditions. Through subsequent simulation runs, the constructed framework was then tested. Requested anthroposphere information was synthesized within a systems model to forecast ecosystem services and human-use dynamics under alternative scenarios. The simulation used the model, the model references and the framework for guidelines, thus allowing multiple simulation / demonstration runs for different contexts or scenarios. The third step was the construction of a PIO checklist which guides criteria testing and provides a means of gaining pertinent information for further studies, based on this dissertation. Framework EMF radiation policy inputs into the model were intersected with identified vulnerable area facilities which were selected based on international criteria. The research output revealed potential EMF radiation violations which served as system feedback inputs in support of a demonstrated PIO function. The research recommends that the identified EMF radiation exposure violations of public health undergo a Promotion of Access to Information Act (PAIA) judicial review process to confirm the research findings. The judicial qualification of a PAIA PIO function of ‘substances released into the environment’ and ‘public safety or environmental risk’ would enable access to EMF radiation emissions data essential to future studies.