Multiple-frequency thickness-mode thin-film piezoelectric-on-substrate filter array

An approach to build thin-film piezoelectric-on-substrate (TPoS) filters working at different frequencies on the same wafer is proposed. In this approach, filters with different substrate layer thicknesses working at different orders of resonance are used. The insertion loss for each thickness and mode is predicted by introducing damping elements in the material constants used in Mason’s model simulations. In a first demonstration, ZnO-on-Si filters with different Si layer thicknesses are fabricated and tested. Measurement results are in good agreement with simulations. Several filters with low insertion loss at different frequencies are fabricated on the same wafer.