| 摘要 |
PROBLEM TO BE SOLVED: To prevent interference between IDTs of respective surface acoustic wave(SAW) elements, even if main surfaces of the SAW elements are arranged opposite each other by arranging the main surfaces of the SAW elements, where inter-digital electrodes are formed opposite each other across a shield plate. SOLUTION: This SAW filter is constituted by arranging two SAW elements 10 and 20 across a shield plate 3 so that their main surfaces face each other. The SAW element 10 has a reed screen type reflector electrode, an input IDT, an output IDT, and a reed screen type interdigital reflector electrode on one main surface of a rectangular piezoelectric substrate in the propagation direction of a surface acoustic wave. Namely, the SAW element 10 is a longitidiaully coupled type SAW filter. The SAW element 20 has a reed screen type reflector electrode, an input IDT composed of a couple of interdigital electrode fingers, an output IDT composed of a couple of interdigital electrode fingers 23a and 23b, and a reed screen type reflector electrode arrayed on one main surface of a rectangular piezoelectric substrate in the propagation direction of a saw- tooth acoustic wave.
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