Resonant Inc.
Transversely-excited film bulk acoustic resonators with structures to reduce acoustic energy leakage

Abstract:

Acoustic resonators, acoustic filter devices and methods of making the same. An acoustic resonator device includes a piezoelectric plate having front and back surfaces, and an interdigital transducer (IDT) on the front surface including interleaved fingers. An overlapping distance of the interleaved fingers defines an aperture of the acoustic resonator device. The device further includes a fast region between the aperture and a busbar of the IDT. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode having a first frequency in the piezoelectric plate within a central portion of the aperture and a primary shear acoustic mode having a second frequency in the fast region. The second frequency is higher than the first frequency.