Patent ID: 8072293
Filing Date: 2011-12-06
Classification: H03H

Abstract:
1. A surface acoustic wave filter comprised of a plurality of surface acoustic wave resonators having different resonance frequencies, the filter comprising: a substrate made of lithium niobate; comb electrodes formed on an upper surface of the substrate; and a thin dielectric film covering the comb electrodes; wherein a metallization ratio of the surface acoustic wave resonator having a lower resonance frequency is larger than a metallization ratio of the surface acoustic wave resonator having a higher resonance frequency; and wherein the plurality of surface acoustic wave resonators comprises at least two surface acoustic wave resonators in a series arm, and a metallization ratio of one of the surface acoustic wave resonators in the series arm having a lower resonance frequency is larger than a metallization ratio of the other surface acoustic wave resonator having a higher resonance frequency.