Surface acoustic wave filter
US5581141A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1994 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Oct 7, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/38
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A SAW resonator disposed with an IDT electrode and reflector electrodes is formed on the surface of a piezoelectric substrate. Three pieces of the SAW resonator form an acoustic coupling by being disposed close to each other, electrode fingers comprising the IDT electrode in the center are all grounded, and IDT electrode fingers are electrically independent on the side to be connected to input-output terminals of the IDT electrodes disposed outside. As a result, three excitation modes having different propagation frequencies are generated which are used to attain a broad band SAW resonator filter. When these three pairs of the IDT electrode are electrically independent, a balanced input-output can be achieved, and excellent out-of-band rejection characteristics can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.