Patent ID: 6011451
Filing Date: 2000-01-04
Classification: H03H

Abstract:
A chip type piezoelectric filter, comprising:a first piezoelectric substrate;a second piezoelectric substrate connected to said first piezoelectric substrate;a first piezoelectric filter section disposed on the first piezoelectric substrate;a second piezoelectric filter section disposed on the second piezoelectric substrate; andat least one coupling capacitor being arranged to electrically connect the first piezoelectric filter section to the second piezoelectric filter section, said at least one coupling capacitor being disposed on at least one of said first and second piezoelectric substrates;wherein each of said first and second piezoelectric filter sections comprise a pair of resonance electrodes provided on one of top and bottom major surfaces of the respective piezoelectric substrate, and a common electrode provided on the other of the top and bottom major surfaces of the respective piezoelectric substrate such that the pair of resonance electrodes and the common electrode oppose each other, and wherein the common electrodes of said first and second piezoelectric filter sections are located at an interior of an integral laminated body defined by the connected first and second piezoelectric substrates in such a way that the surface of the first piezoelectric substrate on which the common electrode is provided and the surface of the second piezoelectric substrate on which the common electrode is provided are opposed to each other.