Surface acoustic wave filter, surface acoustic wave device using the filter, and communications device using the filter or the device

摘要

A small pitch electrode finger portion (108/109) having electrode fingers of which the pitch is smaller than that of the other electrode fingers is provided in the end of at least one (104) of interdigital transducers which is adjacent to the other interdigital transducer (103/105). Moreover, the small pitch electrode finger portion (108/109) contains two adjacent electrode fingers (110,111/112,113) in at least one position thereof which are electrode-inverted so that the polarities of the two adjacent electrode fingers are made the same.