Patent ID: 11870423
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 10:
11. A filter device, comprising:
a substrate;
a lithium niobate plate having front and back surfaces and a thickness ts, the back surface attached to the substrate;
a conductor pattern formed on the front surface, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of resonators including a series resonator and a shunt resonator, interleaved fingers of each of the plurality of IDTs disposed on respective portions of the LN plate suspended over one or more cavities formed in the substrate;
a first SiO2 layer having a thickness tds deposited on one of the front surface and the back surface of the diaphragm of the series resonator; and
a second SiO2 layer having a thickness tdp deposited on one of the front surface and the back surface of the diaphragm of the shunt resonator, wherein
ts, tds, and tdp are related by the equation:

0.875ts≤tds<tdp≤1.25ts.