This thesis is motivated by the need to calculate the electromagnetic fields produced by sources radiating in the presence of conductors. We begin by reviewing existing theory concerning sources in the presence of flat structures. Various extensions to the canonical Sommerfeld problem are considered. In particular we investigate the asymptotic solution for a finite source that focusses its energy at a point. In chapter 5 we review and extend the asymptotic results concerning illumination of a convex perfect conductor by an incident plane wave and outline the procedure for decoupling the electromagnetic surface field into two scalar modes. In chapter 6 we place a source on a perfect conductor and obtain a complete asymptotic solution for the fields. Special attention is paid to the asymptotic structure that smoothly matches between the leading order lit and shadow regions. We also investigate the degenerate case where one of the curvatures of the perfect conductor is zero. The case where the source is just off the surface is also investigated. In chapter 8 we use the Euler-Maclaurin summation formula to cheaply calculate the fields due to complicated arrays of point dipoles. The final chapter combines many earlier results to consider more general sources on the surface of a perfect conductor. In particular we must introduce new asymptotic regions for open sources. This then enables us to consider the focussing of the surface field due to a finite source. The nature of the surface and geometrical optics fields depends on the size of the source in comparison to the curvatures of the surface on which they lie. We discuss this in detail and conclude with the practical example of a spiral antenna.

There exist various models for Microwave MESFET equivalent circuit representations. These models use different mathematical models to describe the same MESFET and give similar results. However, there are some differences in the results when compared to the experimental measurements. In this thesis, various theoretical models are applied to the same MESFET and comparison made with measured data. It is shown that some models worked better on some parameters of the MESFET, while the others were more effective on other parameters. Altogether eight models were examined and data optimized to fit these theoretical models. In using optimization algorithms MATLAB FMINSEARCH and GENETIC ALGORITHM CODE were used alternatively to solve the initial value problem.

Thesis (doctoral)--Otto-von-Guericke-Universität Magdeburg, 2005. / "Dissertation zur Erlangung des akademischen Grades Doktoringenieur (Dr.-Ing.)." "This thesis presents a new method to derive a generalized transmission-line theory, the Transmssion Line Supertheory (TLST)"--p. 13. Includes bibliographical references (p. 127-138).

Thesis (Ph.D.)--Cleveland State University, 2008. / Abstract. Title from PDF t.p. (viewed on May 8, 2008). Includes bibliographical references (p. 121-126). Available online via the OhioLINK ETD Center. Also available in print.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (p. [50]-52).

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Mathematics." Includes bibliographical references (p. 140-143).

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 November 23, 2009) Includes bibliographical references.

A "Geometrodynamical Analog to Electric Charge" (or "p-charge") is defined (as in the earlier paper by Unruh, [Gen. Rel. and Grav., 2, (1971), pp 27-33 ] to be the period on a p-cycle (p = 1, 2, or 3) of a p-form which is constructed out of only the Riemann tensor or its derivatives. A previously-unpublished proof by Unruh is briefly summarized which proves that no non-zero p-charges can exist on a completely unrestricted metric field. The metric field is then constrained to obey Einstein's equations for empty space, and sets of linearly-independent, purely-gravitational p-forms are analyzed to determine if p-charges can be defined under these conditions. A scheme is developed, based on the spin-tensor representation of the gravitational field, to generate complete sets of such p-forms, arid calculate their derivatives, with a symbolic-manipulation computer program. It is shown that no gravitational p-forms that are linear combinations of less than five Riemann tensors and less than nine derivatives will result in p-charges. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20921号 / 理博第4373号 / 新制||理||1628(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 大志万 直人, 准教授 吉村 令慧, 教授 中西 一郎 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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