Title :
An electronically tunable microstrip bandpass filter using thin-film Barium-Strontium-Titanate (BST) varactors
Author :
Nath, Jayesh ; Ghosh, Dipankar ; Maria, Jon-Paul ; Kingon, Angus I. ; Fathelbab, Wael ; Franzon, Paul D. ; Steer, Michael B.
Author_Institution :
Dept. of Electr. & Comput. Eng., North Carolina State Univ., Raleigh, NC, USA
Abstract :
A tunable third-order combline bandpass filter using thin-film barium-strontium-titanate varactors and fabricated on a sapphire substrate is reported. Application of 0-200-V bias varied the center frequency of the filter from 2.44 to 2.88 GHz (16% tuning) while achieving a 1-dB bandwidth of 400 MHz. The insertion loss varied from 5.1 dB at zero bias to 3.3 dB at full bias, while the return loss exceeded 13 dB over the range. The third-order intercept of the filter was found to be 41 dBm.
Keywords :
UHF filters; band-pass filters; barium; microstrip filters; sapphire; strontium; thin film devices; titanium compounds; varactors; 0 to 200 V; 2.44 to 2.88 GHz; 400 MHz; barium-strontium-titanate varactors; combline filter; ferroelectric films; intermodulation distortion; microstrip bandpass filter; microstrip filters; resonators; thin-film BST varactors; thin-film devices; tunable filters; Band pass filters; Bandwidth; Binary search trees; Frequency; Insertion loss; Microstrip filters; Substrates; Transistors; Tuning; Varactors; Barium strontium titanate (BST); combline filter; ferroelectric films; intermodulation distortion; microstrip filters; resonators; thin-film devices; tunable filters; varactor;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2005.854196
