Elastic wave device, high-frequency front-end circuit, and communication apparatus
US10951192B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 2018 |
| Grant date | Mar 16, 2021 |
| Priority date | — |
| Expiry date | Jun 8, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/1027
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An elastic wave device includes a piezoelectric substrate and an interdigital transducer electrode on the piezoelectric substrate, the piezoelectric substrate including a piezoelectric layer and a high-acoustic-velocity member layer, the piezoelectric layer being stacked on the high-acoustic-velocity member layer. The piezoelectric layer is made of lithium tantalate. Denoting an elastic wave propagation direction as a first direction, and a direction perpendicular or substantially perpendicular to the first direction as a second direction, a central region, low-acoustic-velocity regions, and high-acoustic-velocity regions are provided in the interdigital transducer electrode in the second direction. The low-acoustic-velocity regions include mass-adding films on electrode fingers. Denoting a film thickness normalized to a wavelength determined by the electrode finger pitch of the interdigital transducer electrode as a wavelength-normalized film thickness (%), a product of the wavelength-normalized film thickness of the mass-adding films and the density (g/cm3) of the mass-adding films is about 13.4631 or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.