摘要 |
It is possible to reduce the size of a surface acoustic wave (SAW) resonator by enhancing a Q value. In a SAW resonator in which an IDT having electrode fingers for exciting SAW is disposed on a crystal substrate, the IDT includes a first region disposed at the center of the IDT and a second region and a third region disposed on both sides of the first region. A frequency is fixed in the first region and a portion in which a frequency gradually decreases as it approaches an edge of the IDT is disposed in the second region and the third region. When the frequency of the first region is Fa, the frequency at an edge of the second region is FbM, and the frequency at an edge of the third region is FcN, the variations in frequency are in the ranges of 0.9815<FbM/Fa<0.9953 and 0.9815<FcN/Fa<0.9953, respectively.
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