Advisor(s)

Vincent G. Harris

Contributor(s)

Carmine Vittoria, Anton Geiler, Yajie

Date of Award

2011

Date Accepted

5-2011

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 engineering, antenna, electromagnetic band gap metamaterials, oriented, wideband, Z-Type barium hexaferrites

Disciplines

Electrical and Computer Engineering

Abstract

In order to achieve a significant reduction in volume over standard dielectric λsub/4 cavity slot antenna designs, while concurrently maintaining usable gains >2-3 dB, realizable high permeability oriented cobalt-substituted Z-Type barium hexaferrite materials have been introduced through a modified aqueous synthesis technique both as magnetic substrates and as electromagnetic band gap (EBG) metamaterial ground planes. Significant volumetric reduction of antenna elements (92%) due to magnetic and dielectric loading has been achieved via tailoring the permittivity and permeability of the ferrite material through an orientation process over standard λo/4 cavity designs. Further reduction (94% of λo/4 cavity designs) is achieved via combining a realizable high permeability Co2Z hexaferrite (permittivity=16 permeability= 14) with a periodic array of metallic Sivenpiper Structures to create an EBG metamaterial. The thickness of the investigated EBG metamaterial is <λo/125 at the lowest operation frequency. The bandwidth of these metamaterials is investigated in terms of realizable fabrication techniques, and is determined while biased from the phase of a reflected plane wave, as is common in literature, to be >50-75% of the L-Band. Unbiased designs with >50% bandwidth have also been reported. Gains of -2.5 to 2.5 dB have been achieved for both magnetic substrates and EBG ground planes, with a voltage standing wave ratio (VSWR) <2 indicating that these designs are practical for commercial and defense applications which call for low profile miniaturized antenna designs which do not suffer from reduced gain.>Furthermore, these designs have been applied to conformal surfaces increasing the potential applications of these technologies.

Document Type

Dissertation

Rights Information

copyright 2011

Rights Holder

Andrew Paul Daigle


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