End-surface reflection type surface acoustic wave filter

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 resin-coating layer which is provided on the top surface of the piezoelectric substrate so as to cover at least said plurality of interdigital transducers and regions at which the first and the second grooves or the first and the second recess portions are located and which includes a flexible resin;
• wherein the resin-coating layer partially intrudes into at least one of the first and the second grooves or at least one of the first and the second recess portions.