Patent ID: 7135805

Claim:
A surface acoustic wave transducer comprising: a substrate which is piezoelectric or electrostrictive; a first electrode disposed on a surface of said substrate and having a plurality of first electrode fingers; a second electrode disposed on the surface of said substrate and having a plurality of second electrode fingers alternating with said first electrode fingers; and structural elements disposed on the surface of said substrate and arranged periodically in a propagating direction of surface acoustic waves; wherein λ 0 represents a wavelength which corresponds to a fundamental operating frequency of said surface acoustic wave transducer; wherein said structural elements are dielectric films disposed on the surface of said substrate and arranged at periodic intervals of λ 0 /2 in the propagating direction of surface acoustic waves; wherein said first and second electrode fingers are arranged at periodic intervals of λ 0 /2 as electrode fingers and have at least portions thereof which overlap said dielectric films; and wherein said substrate, said dielectric films, and said electrode fingers are stacked in this order in regions where said electrode fingers and said dielectric films overlap each other.