| 摘要 |
PURPOSE: A surface acoustic wave filter for waveguide is provided, in which an inter-digital transducer(IDT) which serves as a reflector is connected to an external input terminal, to thereby reduce unnecessary signal reflection. CONSTITUTION: A surface acoustic wave filter comprises the first resonator and the second resonator positioned at the center of the filter; the first reflector and the second reflector positioned at both sides of the first resonator and the second resonator; and the first coupling pad(54) and the second coupling pad(58) for coupling first and second resonators. The first coupling pad is connected to an input terminal(51) or an output terminal for an electrical connection to an external source. The first coupling pad which is positioned at least between the first resonator and the first reflector, or between the first resonator and the second reflector, is partially separated by a plurality of IDTs, and the second coupling pad is connected to a grounding part(53). The second coupling pad which is positioned at least between the second resonator and the first reflector, or between the second resonator and the second reflector, is partially separated by a plurality of IDTs.
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