Suppressing parasitic sidebands in lateral bulk acoustic wave resonators
US11223341B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2019 |
| Grant date | Jan 11, 2022 |
| Priority date | — |
| Expiry date | Dec 27, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/564
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Acoustic wave filter devices are disclosed. In an embodiment, the device includes an acoustic wave resonator and a reflecting layer located below the acoustic wave resonator. The wave resonator includes an input electrode including a first electrode and a counter electrode, a piezoelectric layer sandwiched between the first electrode and the counter electrode, and an output electrode. The piezoelectric layer has a first region covered by the first or the output electrode, and a second region not covered by any of the first and the output electrode. The first region has a second order acoustic thickness-shear resonance (TS2) mode dispersion curve with a first minimum frequency, and the second region has a TS2 mode dispersion curve with a second minimum frequency. The reflecting layer's thickness is such that a difference between the first minimum frequency and the second minimum frequency is less than 2% of a filter center frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.