Franklin

The pseudochiral omega medium: Theory and potential applications [electronic resource].

Author/Creator:
Saadoun, Mamdouh Mohamed Ibrahim.
Format/Description:
Book
463 p.
Contained In:
Dissertation Abstracts International 53-11B.

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Subjects:
Optics.
Electrical engineering.
Local subjects:
Penn dissertations -- Electrical engineering. (search)
Electrical engineering -- Penn dissertations. (search)
System Details:
Mode of access: World Wide Web.
Summary:
In this work we introduce the concept of the pseudochiral omega ($\Omega$) medium as a subset of the wider set of bianisotropic linear media. The introduction of this novel electromagnetic medium is physically motivated by pointing out its similarity to transversely biased ferrites. We also study, theoretically, the possibility of using the $\Omega$ medium in some novel microwave devices such as tunable cavity resonators and reciprocal phase shifters. The study focuses on the interaction between the conducting $\Omega$ microstructures in the $\Omega$ medium and the electromagnetic fields in such devices. We also introduce the concept of the non-local $\Omega$ medium as a generalization of the pseudochiral $\Omega$ medium. The constitutive relations of such media are given and the wave equation governing the electric field in these materials is presented. From the solution of the wave equation, it is shown that the eigenmodes of propagation in a non-local $\Omega$ medium are linearly polarized uniform plane waves and that the fields of at least one of the eigenmodes strongly interact with the medium. The frequency characteristics of the material parameters of the non-local $\Omega$ medium are derived based on a proposed equivalent-circuit model of the non-local $\Omega$ element. The model yields physically acceptable results except at extremely high frequencies where the circuit-model approximation no longer applies. The plane wave propagation in an unbounded three-dimensional non-local $\Omega$ medium is studied and the equation of the index surface is obtained. The eigenmodes of propagation and their wavenumbers as well as their wave impedances are also given for specific directions of propagation. The reflection and transmission coefficients of an $\Omega$ half-space are obtained and the problem of wave reflection by a lossy $\Omega$ layer in front of a perfectly conducting ground is analyzed theoretically. It is shown that the resonance of the conducting $\Omega$ microstructures in the $\Omega$ medium can enhance energy dissipation in the medium and, therefore, can result in a noticeable reduction in the magnitude of the reflection coefficient. The theory of $\Omega$ waveguides is also developed and the problems of parallel plate and slab waveguides are solved. The radiation problem is tackled by considering the case of a uniform infinite-line current source embedded in an unbounded $\Omega$ medium and the case of such a source above an $\Omega$ half-space. Finally, we present a suggestion for the practical implementation of some of our proposed ideas in the area of microwave devices.
Notes:
Thesis (Ph.D. in Electrical Engineering) -- Graduate School of Arts and Sciences, University of Pennsylvania, 1992.
Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5901.
Supervisor: Nader Engheta.
Local notes:
School code: 0175.
Contributor:
Engheta, Nader, advisor
University of Pennsylvania.
Access Restriction:
Restricted for use by site license.