Publication Date

2018

Document Type

Dissertation/Thesis

First Advisor

Abdel-Motaleb, Ibrahim Mohamed, 1954-

Degree Name

M.S. (Master of Science)

Department

Department of Electrical Engineering

LCSH

Electrical engineering

Abstract

Terahertz is defined as the range from 0.3 THz -- 3 THz or a wavelength from 1000-100 microm. THz can be used in medical imaging, security, communications, scientific instrumentations, and military applications. Because THz radiation is non-ionizing, it is safe for use in medical application. To realize the full advantages of THz radiation, efficient antennas or detectors need to be designed. In this thesis, we designed Bow-Tie antennas using Gold (Au) and Indium Tin Oxide (ITO) on various insulating and semi-conducting substrates. The antennas were analyzed using the finite element, Multiphysics program, COMSOL R. Au was used for its low resistivity and ITO was used for its ability to vertically integrate with optical devices. The Bow-Tie antenna is composed of two triangles facing each other at the apex with a nanometer-gap between them. This gap acts as a capacitor. The absorption of THz radiation results in the creation of an electric field across the gap. The dimensions of the antenna were changed, and the electric field across the gap was calculated. As expected, the results show that the electric field decreases with the gap, it increases with the decrease of the gap dimension. Hence, the minimum size of the gap is related to the critical dimension of the fabrication process. The results show also that the electric field increases with the metal thickness. This can be attributed to the decrease of the antenna resistance as the thickness decreases. On the other hand, the width dimension seems not to affect the output field substantially. This may be because the width affects the magnetic field only and does not affect the electric field measured across the gap. The increase of the Length of the antenna, L, resulted in the decrease of the peak frequency, f0. This is because f0 is proportional to 1/L. Therefore, by combining several antennas with different lengths, we can design a THZ detector with wider range of frequency detection. The behavior of the ITO antennas is the same way as the Au antenna, but with lower field values. This can be attributed to the high resistivity of ITO compared with Au.

Comments

Advisors: Ibrahi, M. Abdel Motaleb.||Committee members: Dr. Suma Rajashankar; Dr. Donald S. Zinger.||Includes illustrations.||Includes bibliographical references.

Extent

86 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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