Title :
Voltage-controlled RF filters employing thin-film barium-strontium-titanate tunable capacitors
Author :
Tombak, Ali ; Maria, Jon-Paul ; Ayguavives, Francisco T. ; Jin, Zhang ; Stauf, Gregory T. ; Kingon, Angus I. ; Mortazawi, Amir
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
Tunable lowpass and bandpass lumped-element filters employing barium-strontium-titanate (BST)-based capacitors are presented. A new metallization technique is used, which improves the quality factor of the tunable BST capacitors by a factor of two. The lowpass filter has an insertion loss of 2 dB and a tunability of 40% (120-170 MHz) with the application of 0-9 V DC bias. The bandpass filter (BPF) has an insertion loss of 3 dB and a tunability of 57% (176-276 MHz) with the application of 0-6 V DC. The third-order intercept point of the BPF was measured to be 19 dBm with the application of two tones around 170 MHz.
Keywords :
Q-factor; VHF devices; VHF filters; band-pass filters; barium compounds; circuit tuning; ferroelectric capacitors; losses; low-pass filters; lumped parameter networks; metallisation; strontium compounds; thin film capacitors; 0 to 6 V; 0 to 9 V; 120 to 170 MHz; 170 MHz; 176 to 276 MHz; 2 dB; 3 dB; BaSrTiO3; DC bias; bandpass lumped-element filters; insertion loss; intermodulation distortion; lowpass lumped-element filters; metallization technique; quality factor; thin-film barium-strontium-titanate tunable capacitors; third-order intercept point; tunability; tunable BST capacitors; voltage-controlled RF filters; Band pass filters; Binary search trees; Capacitors; Insertion loss; Loss measurement; Metallization; Q factor; Radio frequency; Transistors; Voltage;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2002.807822
