| 摘要 |
PROBLEM TO BE SOLVED: To enhance flatness of a filter characteristic within a pass band in a surface acoustic wave filter where a plurality of one-terminal pair surface acoustic wave (SAW) resonators are used to configure a ladder type circuit. SOLUTION: A plurality of the one-terminal pair SAW resonators on a piezoelectric substrate are formed to configure a ladder type circuit having a series arm and at least two parallel arms, and in an inter digital transducer of the one-terminal pair SAW resonators connecting at least to one parallel arm, a gap W2 between bus bars 4, 5 and tips of electrode fingers 7, 6 connecting to the bus bars 5, 4 opposite to the bus bars 4, 5 is configured different from a gap corresponding to the one-terminal pair SAW resonators connecting to the other parallel arm.
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