Piezoelectric Resonator, Piezoelectric Filter, and Duplexer and Communication Device Using the Same

Abstract

Three or more piezoelectric resonators having resonance frequencies different from one another are realized on the same substrate. First through third frequency adjustment layers 107a through 107c of first through third piezoelectric resonators 102a through 102c provided on the same substrate 101 are formed by varying, among the frequency adjustment layers, the ratio of area (depressions 109 and 110) to be etched to area not to be etched.

Dependencies are inferred from the claim text.