Date of Award

January 2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical Engineering

First Advisor

Sima Noghanian

Abstract

This thesis provides an investigation of a Single Layered Periodic Structure Loaded Textile Patch Antenna with probe feed excitation. Specifically, this thesis is concentrated on the application of wearable antenna arrays with space suit, since this thesis has collaboration with the University of North Dakota (UND) Space Suit Laboratory in the Space Studies Department. Topics include; platform interaction and placement of the antenna system. The goal is to increase antenna gain by loading the antenna with periodic cells. First, an introduction to items contained within this thesis will be given. The second chapter introduces microstrip patch antennas, their basic characteristics, and their feeding excitation methods. Continuing with microstip patch antennas, and how they are viewed with their fringing field effects. Then the theoretical designs of the physical dimensions of a patch antenna relative to its electrical length are included. This part then ends with a basic introduction to periodic structures, namely Electromagnetic Band Gap (EBG) structures.

The third chapter covers wearable antennas, with and without periodic structures, and their applications. A review of surface waves and wave modes is given. This review produces a picture of how this once un-utilized energy (i.e. surface waves) can be recycled and reused to benefit positively increased gain. This can be accomplished by use of periodic structures loaded with the antenna. The fourth chapter covers the material, manufacturing, assembling, and measuring processes of textile antennas. This range of processes is journeyed as a joint collaboration between UNDs Electrical Engineering Department's Applied Electromagnetics Laboratory, and the Technology Department's Machine Shop.

Lastly, simulation and design of a periodic loaded patch antenna are analyzed. This begins by first designing and simulating a free standing periodic cell coined "C-mirror". The simulation results for reflection and dispersion characteristics are given. A 1 GHz antenna with specifications of textile material was designed. Once this antenna was realized, it was then loaded uni-planar with periodic cells with no vias. Experiments included varying the orientation, number of rows, and the placement of the cells with respect to the antenna. It was found that the Up-Down (UD) orientation with 2 rows and λo/12 placement demonstrated the greatest increase in gain. Furthermore, surface currents were seen to interact with the periodic cells. It could be seen that the arrangement of the cells adapted a network internally with the current flowing through the cells obtaining an inductive behavior and the capacitive behavior occurred between the cells stubs as well as between the cells defined by the Periodic Boundary Conditions (PBC). This surface current behavior, with the orientation of the periodic array with no vias became known as a "Uni-Planar Parasitic Loaded Patch Antenna".

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