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Investigation on Conformal Planar High-Gain Antennas: Corrugated Antennas and Fabry-Pérot-Type Cavity Antennas
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- Author / Creator
- Honari Kalateh, Mohammad Mahdi
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There are many applications such as radar, space, and satellite communication, which require antenna with high gain while maintaining low profile, planar structure, and low fabrication cost. In this thesis, two techniques are presented to design high-gain antennas with planar structures, numerically, and experimentally. Corrugated structures and miniaturized-element frequency selective surfaces (MEFSSs) are used to improve the radiation gain of corrugated antennas, and Fabry-Pérot-type cavity (FPC) antennas, respectively.
First, for high power applications, TM01 to TE11 mode converters are required to convert the undesired mode of high power source to the desired mode for corrugated antennas. These mode converters are designed for the purpose of achieving high conversion efficiency over wide operational bandwidth. Using 3D printing technology, these mode converters are printed and their performance is experimentally studied.
Conventional corrugated antennas are fabricated on metallic sheets and are fed by open-ended waveguides. In order to reduce the fabrication expense and to easily integrate them with other planar structures, the realization of corrugated antennas on laminates using SIW technology is presented. Due to the large structure of corrugated antennas, the simulation and optimization process are time-consuming. Design and analysis of these antennas based on surface susceptance of corrugated structure are presented in this work. General radiation performance of corrugated antennas such as resonant frequency, spectral bandwidth, and directivity is estimated using a unit-cell analysis of corrugated surface. The effect of width and height of corrugations and the permittivity of material inside corrugations on directivity and surface susceptance is parametrically studied.
The design of dual-band high-gain antennas is a challenging problem, especially if the antennas are required to be planar and fabricated with cheap fabrication processes. In the study of corrugated antennas, it is shown that a dual-band operation can be achieved by using two different corrugations. To improve the front-to-back ratio of the antenna, two dual-band cavity back feeder antennas are proposed to feed the dual-band corrugated structure. The dual-band feeder antennas and dual-band corrugated antennas are fabricated and measured.
Using MEFSS structures in FPC antennas may enhance the antenna gain. This technique is proposed in this work to enhance the radiation of on-chip antenna by utilizing a MEFSS cover on top of it. This is absolutely essential in radio frequency integrated circuits (RFICs) due to the restrictions on the thickness of metallic layers, substrate loss, and the limitations in a real estate. Due to using MEFSS structure, the height of the FPC antenna composed of the MEFSS cover, high impedance surface (HIS), and the a single proximity patch antenna can be designed to be very small. A scaled MEFSS cover is designed and fabricated and the measurement results demonstrate a gain enhancement of 9 dBi. A wideband MEFSS cover is then designed with two MEFSS layers to solve the problem of narrow bandwidth of single-layer MEFSS structure. These MEFSS structures can be used for radiation gain enhancement off of the on-chip antenna. -
- Graduation date
- Fall 2019
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.