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Title:Analysis and test of patch antennas for applications in dual-band and diversity systems
Author(s):Colomb, Francois Yves
Doctoral Committee Chair(s):Mayes, Paul E.
Department / Program:Electrical and Computer Engineering
Discipline:Electrical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Electronics and Electrical
Abstract:In this thesis, a study of patch antennas for applications in dual-band and diversity systems is presented. The dual-band capability is achieved with two patches that are stacked vertically and coupled by an aperture in the lower patch. The aperture provides a convenient way of adjusting the separation between the resonant frequencies of the antenna and represents very little added manufacturing complexity. This configuration is applied to the design of a circularly polarized dual-band antenna satisfying frequency specifications for the Global Positioning System (GPS).
Patch antennas consisting of a single patch or two stacked patches are analyzed with a transmission line (TL) model, in which the TL end-loads and the form of the input impedance are obtained in a novel way. The end-loads are determined from Maxwell's equation for known approximate currents on the patch and polarization currents due to the dielectric slabs. The form of the input impedance is based on the expansion of the Green's function in terms of the eigenfunctions of the source-free TL. A comparison with measurements shows that this analysis provides a simple and accurate model for electrically thin rectangular patch antennas.
A diversity antenna for cellular mobile radio is characterized by field tests performed in a multipath environment. The antenna has two different radiation patterns which can provide a diversity receiver with two branches that are only weakly correlated. Simulated selection diversity demonstrates that a single antenna with multiple pattern capability can be used effectively in a diversity system to reduce fading. This assertion is documented with the distribution of the envelope level, the level crossing rate, the average duration of fades and spectral estimation using the short-time Fourier transform.
Issue Date:1993
Rights Information:Copyright 1993 Colomb, Francois Yves
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9411598
OCLC Identifier:(UMI)AAI9411598

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