Resonant Inc.
TRANSVERSELY EXCITED FILM BULK ACOUSTIC RESONATOR USING ROTATED Y-X CUT LITHIUM NIOBATE

Abstract:

Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate and a lithium niobate (LN) plate having front and back surfaces. The back surface is attached to a surface of the substrate except for a portion of the LN plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the LN plate such that interleaved fingers of the IDT are disposed on the diaphragm. The LN plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic wave in the diaphragm. The Euler angles of the LN plate are [0.degree., .beta., 0.degree. ], where .beta. is greater than or equal to 0.degree. and less than or equal to 60.degree..