Dissertation/Thesis Abstract

Coaxial-Cavity Tunable Filters with Surface Mount Tuning Components
by Anand, Akash, Ph.D., University of California, Davis, 2019, 132; 27663054
Abstract (Summary)

Wireless communications is growing and expanding at an exponential rate with billions of users continuously sending electromagnetic waves in the air. This results in a congested air spectrum with the need for complex communication systems. Filters have served as an essential component in these systems to either pass the desired frequencies or to reject the unwanted frequencies. Over the past few decades, stringent requirements in microwave systems have lead to extensive filter development mostly focused on static or fixed frequency filters. Recently, there has been a growing interest in tunable filters to potentially reduce the complexity of these RF systems. This dissertation develops theory and design guidelines on low-loss fast-switching tunable filters with potential applications in Test and Measurement Systems, Communication Systems, and Electronic Warfare Systems.

The early part of the dissertation focuses on developing theoretically foundation on a coaxial based tunable resonator with surface mount tuning components. The resonator design inherently benefits from ease of assembly, flexibility in tuner choice, and flexibility in cavity technology. In depth analysis of the resonant frequency, tuning range, and unloaded quality factor (Qu) is presented. Measurements show tuning range from 0.5 GHz to 1.2 GHz with Qu of 86 to 206 using solid state varactors in a substrate integrated waveguide cavity, tuning range from 2.43 GHz to 3.45 GHz with Qu of 45-684 using solid state diodes integrated inside metallic air cavities, and Qu of up to 240 at 6.6 GHz using MEMS varactors in micro-machined resonators.

The last chapters extend the tunable resonator design to tunable filter design. For example, tunable bandpass filters, tunable bandstop filters, and tunable dual-band bandpass filters are presented. Introducing dispersive inter-resonator coupling in filters allows for advanced filter designs such as reconfigurable bandwidth filters and adjustable transmission zeros filters. As examples, two-pole filters with one or two transmission zeros, four-pole filters with multiple transmission zeros, and fully reconfigurable filters (tunable frequency, bandwidth and transmission zeros) are presented.

Indexing (document details)
Advisor: Liu, Xiaoguang
Commitee: Gu, Q. Jane, Pham, Anh-Vu
School: University of California, Davis
Department: Electrical and Computer Engineering
School Location: United States -- California
Source: DAI-B 81/8(E), Dissertation Abstracts International
Subjects: Electrical engineering
Keywords: Tunable bandwidth, Tunable Filter, Tunable zeros
Publication Number: 27663054
ISBN: 9781658416559
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