DocumentCode :
40812
Title :
Tunable VHF Miniaturized Helical Filters
Author :
Psychogiou, Dimitra ; Peroulis, Dimitrios
Author_Institution :
Lab. for Electromagn. Fields & Microwave Electron. (IFH), Swiss Fed. Inst. of Technol. (ETH), Zürich, Switzerland
Volume :
62
Issue :
2
fYear :
2014
fDate :
Feb. 2014
Firstpage :
282
Lastpage :
289
Abstract :
In this paper, a miniaturization technique and a tuning concept that enable the realization of highly miniaturized and frequency reconfigurable helical filters are reported for the first time. The proposed filter design is based on tunable helical resonators with an internal volume of only 8.6 cm 3 and variable capacitive loading. A second-order bandpass filter was built and measured as a proof-of-concept demonstrator. The helical filter is manufactured with a CNC process and tuning is achieved through piezoelectrically actuated tuners, which are bonded over the helix apex. A measured center frequency tuning between 257-365 MHz was realized with an insertion loss between 0.3-3.2 dB including connector losses. The measured filter bandwidth varied between 6%-7.7%. Tunable resonators were also manufactured so as to extract the unloaded quality factor. It was measured between 392-639 for a center frequency tuning of 2.5:1 (156.5-395 MHz).
Keywords :
Q-factor; VHF filters; band-pass filters; resonator filters; CNC process; filter design; frequency 156.5 MHz to 395 MHz; frequency reconfigurable filters; helix apex; loss 0.3 dB to 3.2 dB; piezoelectrically actuated tuners; proof-of-concept demonstrator; quality factor; second-order bandpass filter; tunable VHF miniaturized helical filters; tunable helical resonators; variable capacitive loading; Cavity resonators; Copper; Finite element analysis; Frequency measurement; Q-factor; Resonant frequency; Tuning; Bandpass filter; UHF; VHF; capacitive loading; helical resonator; tunable filter;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/TMTT.2013.2294592
Filename :
6693765
Link To Document :
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