Patent ID: 6806796
Filing Date: 2004-10-19
Classification: H03H

Abstract:
An end-surface reflection type surface acoustic wave filter comprising:a piezoelectric substrate including first and second reflection end-surfaces disposed substantially parallel to each other and spaced from each other by a predetermined distance, a top surface, a bottom surface, first and second piezoelectric substrate portions which extend from bottom ends of the first and the second reflection end-surfaces to outside of the filter, and first and second grooves or first and second recess portions open to the outside of the filter, the first and the second reflection end-surfaces and the first and the second piezoelectric substrate portions defining the first and the second grooves or the first and the second recess portions, respectively; a plurality of interdigital transducers disposed on the top surface of the piezoelectric substrate between the first and the second grooves or between the first and the second recess portions; and a layer which includes SiO2 and is arranged so as to cover said plurality of interdigital transducers.