Surface acoustic wave filter with range of a frequency difference between resonance frequencies of series and parallel resonators
US5719537A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 9, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Apr 9, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/6483
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a resonator-type surface acoustic wave filter comprising a lithium tantalate substrate, lithium niobate substrate or lithium tetraborate substrate having a cut plane of high velocity, the direction of propagation of surface acoustic waves is set within the range of (40 deg to 90 deg, 40 deg to 90 deg, 0 deg to 60 deg) as expressed in Eulerian angles, and the frequency difference .increment.f between the resonance frequency frs of series resonators and the resonance frequency frp of parallel resonators is set within a predetermined range formulated with the center frequency, the capacitance Cos of the series resonators and the capacitance Cop of the parallel resonators taken as parameters. Optimum ranges of the required design parameters are thus clarified to assure the resonator-type surface acoustic wave filter of higher performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.