Patent ID: 7049908
Filing Date: 2006-05-23
Classification: H03H

Abstract:
1. A surface acoustic wave device comprising: series surface acoustic wave resonators; and parallel surface acoustic wave resonators, the series surface acoustic wave resonators and the parallel surface acoustic wave resonators being arranged in a ladder configuration; wherein the resonant frequency of at least one of the series surface acoustic wave resonators forming a pass band is lower than the anti-resonant frequency of at least one of the parallel surface acoustic wave resonators forming the pass band; in an inductive area formed by said at least one of the series surface acoustic wave resonators forming the pass band and said at least one of the parallel surface acoustic wave resonators forming the pass band, a capacitive area of at least one of the series surface acoustic wave resonators that is different from said at least one of the series surface acoustic wave resonators forming the pass band or a capacitive area of at least one of the parallel surface acoustic wave resonators that is different from said at least one of the parallel surface acoustic wave resonators forming the pass band is disposed; the resonant frequency of part of the series surface acoustic wave resonators is higher than or equal to the anti-resonant frequency of the parallel surface acoustic wave resonators forming the pass band; and the resonant frequency of part of the series surface acoustic wave resonators is set such that ripples produced by the series surface acoustic wave resonators are excluded from the pass band.