Multi-Function Resonant Microwave Devices
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Authors
Brown, Matthew D.
Date
2024-01-17
Type
thesis
Language
eng
Keyword
antenna , filter , RF , microwave
Alternative Title
Abstract
With increasing performance demands and a limited electromagnetic spectrum, multi-functional resonant devices for RF front-ends are becoming required. Passive resonant devices such as filters and antennas are required for every communication link, and heavily influence the wireless performance through their frequency response. This thesis describes the design of multi-functional devices in terms of both fluidically reconfigurable structures, and singular structures possessing the combined frequency response of two traditional devices.
Fluidically tuned resonant devices are first explored by proposing an equivalent circuit model for dielectric fluids. The model is used to design a tunable microstrip branch line coupler with a tuning range of 19.6%. The concept is extended to design a third-order bandpass filter demonstrating a tuning range of 6.8%, and a phase shifter with a variable phase shift of up to 44 degrees over a 1 GHz bandwidth. Liquid metal is also explored as a tuning mechanism. Here, a tunable quasi-elliptic bandpass filter with two transmission zeros is presented, demonstrating a tuning range of 5.3%.
Single devices possessing an intrinsic filtering function and creating far-field gain are then presented, deemed as filtering antennas. Two dual-band devices implementing Chebyshev responds are first presented using the orthogonal second-order modes with passbands from 22.5 GHz to 30 GHz. Filtering antennas possessing finite transmission zeros are then presented for an improved passband selectivity. Initially, quasi-elliptic filters using the second-order hybrid modes are presented implementing two poles and zeros. Four-fundamental topologies are presented showing an out-of-band selectivity surpassing 50 dB. The cavities are used to design three highly-selective filtering antennas around 16 GHz, each with a fractional-bandwidth (FBW) around 5% and a passband roll-off surpassing 30 dB.
Wideband dual-band filtering antennas are then presented using metasurfaces. A device with two passbands at 19 GHz and 27 GHz demonstrates FBWs of 8% and 11%, with realized gains of 8.34 dB and 10.38 dB, respectively. The device also possess five radiation nulls. Lastly, a device with two passbands at 26.7 GHz and 42.4 GHz is presented with FBWs of 19.7% and 26.5%, and realized gains of 4.65 dB and 4.94 dB, respectively, along with three nulls.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-ShareAlike 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-ShareAlike 4.0 International