A proposal of a bulk acoustic wave filter using piezoelectrically coupled resonators

This paper proposes a new configuration of a bulk acoustic wave (BAW) filter. In contrast with a conventional monolithic crystal filter, the resonators in the proposed filter are not mechanically coupled but they are electrically coupled through an additional piezoelectric layer. Equivalent circuit analysis and simulation results are described. An experimental result to verify the principle is shown. Because the proposed filter configuration is suitable for the silicon diaphragm structure with ZnO piezoelectric thin films, the filter can adopted for UHF band filters