Overflateakustisk b°lgetransduser

摘要

A surface acoustic wave transducer with a piezoelectric substrate and at least two electrodes on the surface of the substrate wherein the electrodes comprise fingers which overlap with the fingers of another electrode in a projection parallel to the surface of the substrate is described. The fingers comprise coupling fingers which are located adjacent to a finger of another electrode and which have a high coupling efficiency to the surface acoustic waves. A structure with low surface acoustic wave reflection is located between at least two coupling fingers of the same electrode and the surface acoustic wave propagation velocity of the low reflecting structure and the coupling fingers is equal. Furthermore, a filter comprising the transducer is proposed.