Title :
Narrowband Barium Strontium Titanate (BST) tunable bandpass filters at X-band
Author :
Feng, Zhiping ; Fathelbab, Wael M. ; Lam, Peter G. ; Haridasan, Vrinda ; Maria, Jon-Paul ; Kingon, Angus I. ; Steer, Michael B.
Author_Institution :
Dept. of Electr. & Comput. Eng., North Carolina State Univ., Raleigh, NC, USA
Abstract :
A 3rd-order combline tunable filter with very narrow bandwidth at X-band is implemented utilizing ferroelectric barium strontium titanate (BST) interdigitated varactors. The filter and its varactors are integrated on a ceramic substrate together with a simple resistive biasing circuit. Upon the application of a bias voltage ranging from 0 to 90 V the passband of the filter tuned from 8.127 to 9.973 GHz while maintaining a fractional bandwidth of approximately 4.8-5.9 %. Over the tuning band the passband insertion loss varied from 10.7 dB to 7.5 dB while the return loss was better than 15 dB. The tuning ratio is 23 %.
Keywords :
band-pass filters; barium compounds; ferroelectric capacitors; strontium compounds; varactors; BaSrTiO3; X-band; barium strontium titanate; ceramic substrate; ferroelectric BST interdigitated varactor; frequency 8.127 GHz to 9.973 GHz; tunable bandpass filter; tunable combline filter; voltage 0 V to 90 V; Band pass filters; Bandwidth; Barium; Binary search trees; Narrowband; Passband; Strontium; Titanium compounds; Tunable circuits and devices; Varactors; Barium Strontium Titanate; ferroelectrics; interdigitated capacitors; tunable combline filter;
Conference_Titel :
Microwave Symposium Digest, 2009. MTT '09. IEEE MTT-S International
Conference_Location :
Boston, MA
Print_ISBN :
978-1-4244-2803-8
Electronic_ISBN :
0149-645X
DOI :
10.1109/MWSYM.2009.5165883
