Tunable Resonator Employing Comb-shaped Transmission Line and Semiconductor Switches

Kunihiro KAWAI  Daisuke KOIZUMI  Hiroshi OKAZAKI  Shoichi NARAHASHI  

IEICE TRANSACTIONS on Electronics   Vol.E97-C    No.8    pp.795-802
Publication Date: 2014/08/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E97.C.795
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
Tunable resonators,  microstrip lines,  switches,  

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This paper presents a simple-structured tunable resonator employing semiconductor switches that can change its resonant frequency discretely but precisely. The tunable resonator comprises a transmission line with a comb-shaped pattern and multiple single-pole single-throw (SPST) switches placed between the teeth of the comb-shaped pattern. The resonator changes its resonant frequency according to the switch states, by controlling the path length carrying a high frequency current. The characteristics of the proposed resonator are evaluated through both method of moment electromagnetic simulation and fabrication, using GaAs FET SPST switches. The fabricated resonator changes its resonant frequency from 1.63 GHz to 1.85 GHz. This paper also introduces two circuit designs based on the proposed resonator that expands the tuning range of the resonant frequency or the number of resonant frequencies to be obtained.