A Tunable High Temperature Superconducting Bandpass Filter Realized Using Semiconductor Varactors

Author

Chunguang Li ; Yongbo Bian ; Guoqiang Li ; Yun Wu ; Jia Wang ; Xu Wang ; Xueqiang Zhang ; Fengjin Xia ; Dandan Bai ; Liang Sun ; Hong Li ; Yusheng He

Author_Institution

Nat. Lab. for Supercond., Inst. of Phys., Beijing, China

Volume

24

Issue

5

fYear

2014

fDate

Oct. 2014

Firstpage

1

Lastpage

5

Abstract

This paper presents a semiconductor varactor tuned four-pole bandpass filter. The filter was designed to have a constant fractional bandwidth of 3% and was tuned with single control voltage. The design methods of how to keep coupling coefficients constant and to make all the resonators tuned synchronously are described in details. The filter was built on a two-inch double-side high temperature superconducting film. The center frequency of the filter can be tuned from 430 to 720 MHz with the direct voltage up to 20 V. The return loss is better than 10 dB in the whole tuning range. Insertion loss is in a range of 0.8~3.8 dB with 3 dB fractional bandwidth about 3%.

Keywords

band-pass filters; high-temperature superconductors; resonators; superconducting filters; superconducting thin films; varactors; center frequency; coupling coefficients; design methods; direct voltage; double-side high temperature superconducting film; fractional bandwidth; frequency 430 MHz to 720 MHz; insertion loss; resonators; return loss; semiconductor varactor tuned four-pole bandpass filter; single control voltage; tunable high temperature superconducting bandpass filter; Band-pass filters; Capacitance; Couplings; Resonant frequency; Resonator filters; Superconducting filters; Varactors; High temperature superconducting (HTS); single control voltage; tunable filter; varactor;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2014.2344751

Filename

6870429