High coupling, low loss saw filter and associated method
US8294330B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 2009 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Dec 25, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/02834
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A surface acoustic wave device with improved temperature characteristics includes a piezoelectric substrate of a single crystal of symmetry 3m, providing propagation of a SAW having an electromechanical coupling factor exceeding 5%, an electrode pattern on a substrate surface forming a resonator, and a SiOx overlay covering the electrode pattern. An optimized thickness of the electrodes combined with an SiOx overlay provide improved performance in RF applications with improved temperature characteristics. To suppress spurious responses the SiOx thickness is varied depending upon the relative thickness and period of the electrodes. The electrode pattern forms resonators with the silicon oxide thickness over the electrodes inversely related to the period of the electrodes of the resonators.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.