A UHF 4th-order band-pass filter based on contour-mode PZT-on-Silicon resonators

A UHF 4th-order band-pass filter (BPF) based on the subtraction of two 2nd-order contour-mode resonators with slightly different resonance frequencies is presented. The resonators consists of a 1 μm pulsed-laser deposited (PLD) lead zirconate titanate (PZT) thin-film on top of a 3 μm silicon (PZT-on-Si). The resonators are actuated in-phase and their outputs are subtracted. Utilizing this technique, the outputs of the resonators are added up constructively while the feed-through signals are eliminated. The BPF presented a bandwidth of approximately 28.6 MHz and more than 30 dB stopband rejection at around 700 MHz.