Surface acoustic wave filter utilizing a transmission line with phase characteristics that increase filter out of band attenuation
US6404302B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 2000 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Sep 5, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/6483
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a surface acoustic wave (SAW) filter which is used for cellular phones and other mobile communication equipment. The object of the present invention is to realize a SAW filter of which attenuation characteristics and pass characteristics can be set arbitrarily. The SAW filter of the present invention comprises comb-shaped electrodes facing each other disposed on the same piezoelectric substrate, at least two resonators with an input and output terminals, and an equivalent transmission line which is connected between an output terminal of a first resonator and an input terminal of a second resonator. The phase of the transmission line can be adjusted from 5 degrees to 175 degrees arbitrarily at the series resonance frequency of the resonators. This structure realizes a band-stop filter or a band-pass filter whose attenuation characteristics and pass characteristics can be set arbitrarily.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.