Piezoelectric filter

摘要

A piezoelectric filter in which an earth electrode is provided in the center of a piezoelectric substrate in the direction of thickness; an input electrode is provided on the upper surface of the piezoelectric substrate so as to be opposed to one part of the earth electrode; an output substrate is provided on the lower surface of the piezoelectric substrate so as to be opposed to another part of the earth electrode except the aforementioned one part; a first dummy electrode is formed on the upper surface of the piezoelectric substrate so as to be opposed to the output electrode through the piezoelectric substrate; and a second dummy electrode is formed on the lower surface of the piezoelectric substrate so as to be opposed to the input electrode through the piezoelectric substrate.