High-frequency ladder type piezoelectric filter and piezoelectric resonator therefor

摘要

A ladder type piezoelectric filter of the present invention is made usable in high frequency ranges by employing a piezoelectric resonator having the second harmonic wave mode SM. A series resonator and a parallel resonator of the ladder type piezoelectric filter of the present invention are so arranged that center electrode regions and outer electrode regions are mutually polarized along opposite directions, and the center electrode regions are connected to the outer electrode regions, respectively.