Saw filter with wave reflections and phase differences
US5663696A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 24, 1995 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Apr 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/6493
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A SAW filter comprising a group of N tracks, where N is an odd integer greater than 2, and including an input interdigitated transducer (IDT) spaced apart from an output IDT. The respective tracks are selectable to have different effective electro-acoustic lengths such that surface acoustic waves launched from respective input IDTs undergo at least one reflection at corresponding output IDTs and at least one reflection from the respective input IDTs prior to generating coherent signals from respective output IDTs. The different effective electro-acoustic lengths may be substantially provided by there being different physical separation between input and output IDTs of respective tracks, or by IDTs of respective tracks having different polarity connections of electrodes or different amounts of material deposited in respective tracks between the input and output IDTs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.