Advisor(s)

Edwin A. Marengo

Contributor(s)

Anthony J. Devaney, Philip E. Serafim

Date of Award

2008

Date Accepted

9-2008

Degree Grantor

Northeastern University

Degree Level

Ph.D.

Degree Name

Doctor of Philosophy

Department or Academic Unit

College of Engineering. Department of Electrical and Computer Engineering.

Keywords

Electrical and computer engineering, Metamaterials, Inverse source problems

Subject Categories

Nanostructured materials, Casimir effect

Disciplines

Engineering

Abstract

This dissertation is divided into two parts. The first part solves the full-vector, electromagnetic inverse source problem of synthesizing an unknown source embedded in a given substrate medium of volume V and radiating a prescribed exterior field. Importantly, the derived formulation is non-antenna-specific. It comprises forward, or radiation, characterization as well as inverse-theoretic characterization. The forward characterization is focused on the singular value spectrum while the inverse-theoretic characterization is performed via the ""minimum-energy"" sources. Particular attention is given to the case of two nested spheres made up of materials with oppositely signed constitutive parameters. We find that, for a given antenna radiating at a prescribed frequency, the singular values spectra exhibit resonances that correspond to maximum radiation enhancements. These resonances are primarily due to the presence of polaritons which, in turn, correspond to sets of constitutive parameters that maximize the radiated fields. We also find that for electrically small antenna systems made up of materials with oppositely signed constitutive parameters the emergence of resonances depends on the ratio of the two radii rather than on the overall size of the system. The second part of this dissertation explores the effects that the presence of electromagnetic metamaterials would have on the Casimir forces. Along with their companion van der Waals forces, the Casimir forces, are identified as the primary cause for the collapse of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). Hence, it is crucial for the future development of nanotechnology to investigate the possibility of shielding these potentially destructive forces. One such avenue is explored by means of electromagnetic metamaterials. A surface modes sum is performed to derive an analytic expression for the Casimir force in a dispersive four-region system with planar geometry. In the case of two perfectly conducting plates separated by two media, the numerical simulations demonstrate that the Casimir force is characterized by a new singular behavior in the presence of DPS-DNG combinations. The possible utilization of such systems for the shielding of MEMS and NEMS and for the realization of quantum levitation is discussed. The theoretical studies are accompanied by numerical illustrations.

Document Type

Dissertation

Rights Information

Copyright 2008

Rights Holder

Mohamed-Rabigh Khodja


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