Surface acoustic wave device comprising an interdigital transducer having omitted fingers

摘要

A withdrawal transducer structure is employed in a narrow-band surface acoustic wave device requiring many pairs of interdigital transducer fingers or in a high-frequency surface acoustic wave device in which the thickness of interdigital transducer fingers is large relative to the wavelength of the surface acoustic wave, so that the interdigital transducer fingers may not severely adversely affect the characteristics of the device. The interdigital transducer fingers in the input and output piezoelectric transducers are suitably partly omitted leaving some of them or dummy fingers are additionally provided to eliminate the adverse effect of the interdigital transducer fingers on the characteristics of the device, so that the narrow-band or high-frequency surface acoustic wave device can operate with improved performance without having any unnecessary frequency response.