Bandpass filter with frequency separation between shunt and series resonators set by dielectric layer thickness
US11888465B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2021 |
| Grant date | Jan 30, 2024 |
| Priority date | — |
| Expiry date | Jun 16, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N30/877
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An acoustic filter includes a piezoelectric plate on a substrate. Portions of the piezoelectric plate form one or more diaphragms, each diaphragm spanning a respective cavity in the substrate. A conductor pattern on a front surface of the piezoelectric plate includes interdigital transducers (IDTs) of acoustic resonators including a shunt resonator and a series resonator. Interleaved fingers of each IDT are on a diaphragm of the one or more diaphragms. A first dielectric layer with a first thickness is between the fingers of the IDT of the shunt resonator, and a second dielectric layer with a second thickness less than the first thickness is between the fingers of the IDT of the series resonator. The piezoelectric plate and the IDTs are configured such that radio frequency signals applied to the IDTs excite respective primary shear acoustic modes within the diaphragms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.