Date of Award

Spring 2012

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering - (M.S.)

Department

Electrical and Computer Engineering

First Advisor

Edip Niver

Second Advisor

Gerald Martin Whitman

Third Advisor

Ali N. Akansu

Abstract

Modern communication applications at UHF frequencies require antennas with wide band, high forward gain, low backward radiation, high cross-polarization, small size and low manufacture cost. The Moxon antenna based on a two element Yagi-Uda antenna over the ground reflector is one of the most favorite antennas for HAM operators which can produce outstanding front to back ratio of radiated power, good match over the desired band and relatively low elevation height.

A sequence of topologies has been proposed from a single vertical element to two vertical elements of the Moxon arms, until the lately patented Broadband Circularly Polarized Moxon Based Antennas for UHF satellite communications (SATCOM). The logic was to obtain the best possible performance based on Fano-Chu limits for electrically small antenna with maximum radiating elements in a given volume. This dissertation is an extension of this configuration to cover Radio Frequency IDentification (RFID) (850 MHz-1050 MHz) and Global Positioning System (GPS) (centered at 1227 MHz and 1575 MHz) bands. Prototype antennas are built based on HFSS-11 simulations and experimental measurements yielded satisfactory results. Various design parameters of the proposed complex antenna are optimized to obtain a significant size reduction and much improved performance than the commercial counterpart antennas.

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