Surface acoustic wave filter utilizing a transducer having interdigital electrodes and continuously adjacent electrodes

摘要

A surface acoustic wave filter according to the present invention has one or a plurality of filter functional units each comprising a series arm resonator and a parallel arm resonator. Each of the series arm resonator and the parallel arm resonator is constituted by a interdigital transducer and grating reflectors formed on a piezoelectric substrate composed of 64°-rotated Y-cut X-propagating LiNbO.sub.3. The series arm resonator is constructed by electrically connecting a one-port resonator in series with a signal line, and the parallel arm resonator is constructed by electrically connecting a one- port resonator in parallel with the signal line. In the interdigital transducer in the series arm resonator and/or the parallel arm resonator, one or more sets of electrode fingers continuously adjacent to each other are formed.