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

A longitudinally coupled resonator type surface acoustic wave filter comprising:

• a piezoelectric substrate;
• and
• at least two interdigital transducers arranged on the piezoelectric substrate along a direction in which a surface acoustic wave is propagated;
• wherein
• at least one of the at least two interdigital transducers includes a small pitch electrode finger portion at one end thereof which is adjacent to the other of the at least two interdigital transducers, the small pitch electrode finger portion having electrode fingers of which a pitch is smaller than that of the other electrode fingers in said at least one of the at least two interdigital transducers;
• the small pitch electrode finger portion including two adjacent electrode fingers in at least one position thereof which are electrode-inverted such that the polarities of the two adjacent electrode fingers are the same.