8 to 13 GHz tunable filter based on sol-gel BCTZ varactors

This paper presents the first tunable filter based on sol-gel Barium Calcium Zirconate Titanate (BCTZ) thin ferroelectric film for RF frequencies. The filter is a two pole filter based on varactor loaded CPW lines. Its center frequency can be continuously tuned from 7.95 to 13.05 GHz (64% tuning range) with a 20 V bias voltage. Its figure of merit is 17.3 dB
^-1
/kV which is the best reported for this frequency band.