Patent ID: 11901874
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 6:
7. A filter device, comprising:
a substrate;
a piezoelectric layer having parallel front and back surfaces and a thickness ts, the back surface attached to the substrate either directly or via at least one intermedia layer;
a conductor pattern at the piezoelectric layer and including a plurality of interdigital transducers (IDTs) of a respective plurality of resonators including a shunt resonator and a series resonator, interleaved fingers of each of the plurality of IDTs at respective portions of the piezoelectric layer over one or more cavities;
a first dielectric layer having a thickness tds deposited over and between the fingers of the series resonator; and
a second dielectric layer having a thickness tdp deposited over and between the fingers of the shunt resonator, wherein
ts, tds, and tdp are related by the equations:

2ts=λ0,s, and

2tds<2tdp

where λ0,s is a wavelength of a fundamental shear bulk acoustic wave resonance in the piezoelectric layer.