Surface acoustic wave ring filter
US4155057A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1977 |
| Grant date | May 15, 1979 |
| Priority date | — |
| Expiry date | Oct 31, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/6489
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A surface acoustic wave low loss filter device having input and output transducers located along opposed sides of a rectangular propagation path with frequency selective reflective gratings at each of the four corners of the rectangle. Two traveling surface waves traverse the device along opposed paths encountering frequency filtering at the gratings. The two waves arrive at the output transducer additively in phase eliminating the bidirectionality loss normally associated with surface acoustic wave devices. At frequencies for which the gratings are reflective there can be nearly lossless transmission from input to output. At all other frequencies, transmission between input and output transducers is negligible. The device has high sidelobe rejection, adjustable passband skirt slopes, and an adjustable bandwidth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.