Trw Limited

Jay D Cushman

Robert Bruce Stokes

Drew Cushman

A low frequency mechanical resonator that resonates at relatively low frequencies and can be fabricated as part of an integrated circuit. The resonator includes a piezoelectric structure having a top piezoelectric layer and a bottom piezoelectric layer positioned over a recessed area in a substrate. A top input electrode is positioned on the top surface of the top piezoelectric layer, a middle shield electrode is positioned between the piezoelectric layers, and a bottom output electrode is positioned on the bottom surface of the bottom piezoelectric layer adjacent the recessed area. By applying an appropriate alternating current to the top electrode, the top piezoelectric layer is alternately contracted and expanded. Because the top piezoelectric layer is secured to the bottom piezoelectric layer, the piezoelectric structure will flex up and down in order to relieve stress within the structure. The flexing of the piezoelectric structure causes flexural waves within the piezoelectric structure which resonate at a particular frequency depending on the membrane material, membrane thickness, and the width of the recessed area. The top and bottom electrodes can be replaced with interdigital transducers in order to select particular higher order flexural resonances for higher resonant frequencies.

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Long Beach, CA, United States of America

Jay D Cushman