Saw filter including electrodes of opposing polarity
US5646584A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1995 |
| Grant date | Jul 8, 1997 |
| Priority date | — |
| Expiry date | Apr 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/0285
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A SAW filter having an even number of tracks, each track comprising reflective input and output IDTs having a partially reflecting grating disposed between them. One of the IDTs of each pair of tracks has its electrodes connected in opposite polarity to those of the other IDTs of the pair of tracks and the separation of the input and output IDTs of respective tracks of each pair of tracks is substantially the same. The relative dispositions of the partially reflecting gratings are such that waves launched into respective tracks of a pair of tracks undergo at least one reflection from the partially reflecting grating prior to being coherently incident on the output IDTs. By virtue of the oppositely connected electrodes of one of the IDTs, direct coupling through the tracks is inhibited at substantially all frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.