A theoretical study of electromagnetic feedforward/feedbackward media and wire media.

Format:

Book

Thesis/Dissertation

Author/Creator:

Moses, Charles Anthony.

Contributor:

Laker, Kenneth, advisor.

Engheta, N. (Nader), advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Electrical engineering.

0544.

Penn dissertations--Electrical engineering.

Electrical engineering--Penn dissertations.

Local Subjects:

Penn dissertations--Electrical engineering.

Electrical engineering--Penn dissertations.

0544.

Physical Description:

246 pages

Contained In:

Dissertation Abstracts International 59-04B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

We present our theoretical work in analyzing the electromagnetic properties of classes of complex media that we have introduced and named FeedForward/FeedBackward (FF/FB) Media and Wire media. An artificial FF/FB medium is conceptually proposed as follows: first, as in conventional artificial material, one randomly distributes many electrically small conducting objects throughout some host medium; then one conceptually links every inclusion to one other inclusion some fixed macroscopic distance away. This link can be achieved by means of a tiny two-wire transmission line. In this way, each end-inclusion is influenced not only by the electromagnetic fields interacting directly with that inclusion, but also by the electromagnetic fields interacting with the opposite end-inclusion.

Since, in general, plane waves can interact directly with the wires of the tiny transmission lines, we also consider an approach toward understanding these interactions. Unlike the end-dipoles, the wires of the tiny transmission lines are not necessarily short and can, in principle, be many wavelengths long. As a step toward characterizing wave interaction with these lines, we remove the end inclusions and replace each tiny transmission line by a single wire of equivalent radius. Such media, conceptually constructed from many parallel finite-length wires, we have named Wire Media. We theoretically investigate the propagation of plane waves through wire media and, from this knowledge, determine effective constitutive parameters. One of the main aspects of the present research is the generalization of effective media theory from a theory that usually requires the inclusions to be small, to a theory that permits the inclusions to be large under certain circumstances, provided the periodicities of the periodic structure model are still small.

Our theoretical study shows that FF/FB and wire media possess some interesting electromagnetic properties, such as the possibility of exclusion of wave propagation from certain angular regions depending upon wave polarization, frequency, and chosen design parameters of the medium. This and other features may offer some advantages in engineering materials for future designs of devices and components such as substrates for printed antennas to limit mutual coupling; radomes for beam shaping; and waveguides for mode control.

Notes:

Thesis (Ph.D. in Electrical Engineering) -- University of Pennsylvania, 1998.

Source: Dissertation Abstracts International, Volume: 59-04, Section: B, page: 1787.

Advisers: Nader Engheta; Kenneth Laker.

Local Notes:

School code: 0175.

ISBN:

9780591828160

Access Restriction:

Restricted for use by site license.