Discrete Barium Strontium Titanate (BST) Thin-Film Interdigital Varactors on Alumina: Design, Fabrication, Characterization, and Applications

Comparison of barium strontium titanate varactors on magnesium oxide and alumina substrates

“…The highest tunability observed at 90 Volts for an IDC on alumina was 33.8% and 25.8% on MgO. Previous studies have shown tunability of 33% on alumina at lower DC voltages (116 kV/cm) [9] and up to 65% on MgO [10]. Although the tunability reported here is less than that reported previously, it is still enough for nonlinear characterization.…”

“…The nonlinear behavior of the IDCs was observed by taking two-tone measurements at 0 Volts. Theoretically, this is the applied DC voltage where the devices are most nonlinear [9]. Maury Microwave's Automated Tuning System along with one of the thru lines from the TRL calibration was used to calibrate the two-tone testbench before measuring the IDCs.…”

Tunable RF-Filter Using Mn-Doped BST Ceramic Varactors

“…Potential candidates of varactors currently under investigation are based on semiconductor diodes [1], RF-MEMS switches [2] and variable dielectrics (e.g. BST [3][4][5]). Then, the choice is performed according to desired applications.…”

Microwave study of tunable planar capacitors using mn-doped ba0.6sr0.4tio3 ceramics

“…For example, highly tunable ferroelectric capacitors with q factor of 50 up to 30 GHz were recently demonstrated with both planar [6] and parallel-plate [7] structures. Good performance figures were also obtained with phase shifters [8], [9] or filters [10], [11]. current advances in performance (i.e., compromise between tuning capabilities and insertion losses) are limited by the intrinsic properties of bsT whatever the chosen composition is (i.e., ba/sr ratio in the final compound).…”