Date of Award

2018

Document Type

Open Access Dissertation

Department

Electrical Engineering

Sub-Department

College of Engineering and Computing

First Advisor

Mohammod Ali

Abstract

Structurally integrated conformal antennas offer significant advantages over traditional bolt on antennas, especially for air vehicle applications. The ability to leverage the entire structure allows for unconventionally large antennas and arrays to be implemented in a manner which does not detract from the aerodynamic, structural or aesthetic qualities of the vehicle. Works along this line have included Slotted Waveguide Antenna Stiffened Structures (SWASS), conformal helix and spiral antennas, Log Periodic Dipole Arrays (LPDA), and other antennas.

An area which has not been investigated to date is the possibility of implementing reconfigurable antennas in a structural environment. There are inherent challenges with this approach including the performance of electronic switches when embedded in structural epoxy, the use of non-standard substrates on RF performance, process challenges brought about by using uncommonly large substrates with severe temperature restrictions as antenna substrates, and the use of additively manufactured conducting traces as a surface for MEMS instrumentation. These challenges or bottlenecks are addressed in detail in this dissertation.

This dissertation presents the ideas and methods associated with creating structurally embedded frequency reconfigurable aperture coupled patch antennas for implementation in scanning phased arrays. A MEMS reconfigurable wideband pixelated patch antenna for 1-2 GHz frequency range is presented. This antenna demonstrates 41% bandwidth with 7.2 dB peak gain on one tenth of a wavelength thick structure at 1.8GHz. A similar MEMS reconfigurable 1-2GHz antenna using additively manufactured conducting traces on structural laminates is presented next. Measured results demonstrate nearly 41% bandwidth with 7.8dB peak gain. A 4-band varactor diode reconfigurable pixel patch antenna with 54% bandwidth and 7.5dB peak gain is designed for use in a conformal phased array. Finally, a 6-element, 4-band varactor reconfigurable phased array antenna is presented. The 5ft long array contains 1080 varactor diodes and numerous ultra-thin graphite fibers. Measured results demonstrate array performance from 400-720MHz with a peak gain value above 13dB. The array successfully demonstrates broadside and 35° beam steering throughout the entire frequency range.

Rights

© 2018, Michael Damon Wright

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