Elastische Oberflächenwellenfilter

An elastic surface wave filter which includes a piezoelectric substrate (6) having an electromechanical coupling factor (K ) higher than 10%, three sets in total of input electrodes (3) and output electrodes (4) respectively including a plurality of electrode fingers (7, 8) of comb shape, and formed the piezoelectric substrate (6), and reflectors (5) disposed at opposite sides of the input electrodes and output electrodes. The number of pairs of electrode fingers (7) of the input electrodes (3) is differentiated from the number of pairs of electrode fingers (8) of the output electrodes (4). By the above arrangement, a large pass-band width can be obtained at small ripples, with an increase of the attenuation amount outside the band region.