SURFACE ACOUSTIC WAVE FILTER, ANTENNA DUPLEXER AND METHOD FOR MANUFACTURING THEM

摘要

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 a lithium niobate, comb electrodes (1201 and 1202) formed on the substrate, and a thin dielectric film covering the comb electrodes (1201 and 1202), wherein the surface acoustic wave resonator having a lower resonance frequency is formed to have a metallization ratio larger than a metallization ratio of the surface acoustic wave resonator having a higher resonance frequency, thereby providing the surface acoustic wave filter and an antenna duplexer featuring superior characteristics with insignificant ripples while suppressing spurious responses of the surface acoustic wave resonators.