Boundary acoustic wave device

Abstract

An elastic boundary wave device employing an SH type elastic boundary wave having a large electromechanical coupling coefficient, a low propagation loss, a small power flow angle, a temperature coefficient of frequency TCF in an appropriate range, and a simple structure which can be produced through a simple process. A dielectric is deposited on one side of a piezoelectric and an IDT and a reflector are arranged as electrodes on the boundary of the piezoelectric and the dielectric, wherein the thickness of the electrodes is set such that the sound velocity of the SH type elastic boundary wave becomes lower than the sound velocity of a slow transverse wave propagating through the dielectric and the sound velocity of a slow transverse wave propagating through the piezoelectric.

Description

technical field

[0001] The present invention relates to a boundary acoustic wave device utilizing SH-type boundary acoustic waves, and more particularly, to a boundary acoustic wave device having a structure in which electrodes are provided at the boundary between a piezoelectric substance and a dielectric substrate. Background technique

[0002] So far, various surface acoustic wave devices have been used for RF and IF filters in mobile phones, resonators in VCOs, and VIT filters in TVs. Surface acoustic wave devices use Rayleigh waves or first leaky waves propagating along the surface of a medium.

[0003] Since it propagates along the surface of the medium, surface acoustic waves are sensitive to the surface conditions of the medium. Therefore, in order to protect the surface of the medium along which the surface acoustic wave propagates, the surface acoustic wave element has been sealed in a housing having a cavity portion in which the above-explained surface is placed....

Images