Patent ID: 6064282
Filing Date: 2000-05-16
Classification: H03H

Abstract:
A piezoelectric filter, comprising:a piezoelectric substrate having a first major surface and a second major surface opposed to each other and at least one side edge surface located between the first and the second major surfaces;a plurality of resonating units each of which includes a pair of resonance electrodes provided on the first major surface of the piezoelectric substrate with a gap between the pair of resonance electrodes and a common electrode provided on the second major surface and opposed to the pair of resonance electrodes such that the piezoelectric substrate is located therebetween; anda coupling capacitance unit including a pair of coupling capacitance electrodes each provided on a respective one of the first and the second major surfaces of the piezoelectric substrate and opposed to each other such that the piezoelectric substrate is located therebetween; whereinat least one of the coupling capacitance electrodes extends to the at least one side edge surface of the piezoelectric substrate; andone of the pair of coupling capacitance electrodes on the first major surface extends to at least one side edge of the piezoelectric substrate and the other of the pair of coupling capacitance electrodes on the second major surface extends on to at least one side edge surface of the piezoelectric substrate.