Patent ID: 11870424
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A filter device, comprising:
a piezoelectric plate comprising a supported portion, a first diaphragm, and a second diaphragm, wherein a back surface of the supported portion is attached to a substrate and each of the first and second diaphragms spans a respective cavity in the substrate;
a first interdigital transducer (IDT) on a front surface of the piezoelectric plate, interleaved fingers of the first IDT on the first diaphragm;
a second interdigital transducer (IDT) on the front surface of the piezoelectric plate, interleaved fingers of the second IDT on the second diaphragm;
a first dielectric layer on the front surface of the piezoelectric plate between the interleaved fingers of the first IDT; and
a second dielectric layer on the front surface of the piezoelectric plate between the interleaved fingers of the second IDT,
wherein a thickness of the first dielectric layer is greater than a thickness of the second dielectric layer, and
the piezoelectric plate and the first and second IDTs are configured such that radio frequency signals applied to the first and second IDTs excite primary shear acoustic modes in the respective diaphragms.