Patent ID: 8358177

Claim:
A surface acoustic wave resonator in which an interdigital transducer having electrode fingers for exciting surface acoustic waves is disposed on a piezoelectric substrate, wherein the interdigital transducer includes a first region disposed at the center of the interdigital transducer and a second region and a third region disposed on both sides of the first region, wherein a frequency is fixed in the first region and a portion in which a frequency gradually decreases as it approaches the edge of the interdigital transducer from a part adjacent to the first region is disposed in the second region and the third region, and wherein when the frequency of the first region is Fa, the frequency at an edge of the second region on the opposite side of the first region is Fb M , and the frequency at an edge of the third region on the opposite side of the first region is Fc N , the variations in frequency at the edges are in the ranges of 0.9815<Fb M /Fa<0.9953 and 0.9815<Fc N /Fa<0.9953, respectively.