| 摘要 |
PROBLEM TO BE SOLVED: To improve phase difference balance in a balance input terminal or a balance output terminal and suppress spurious signals in a pass band, in a surface acoustic wave device. SOLUTION: The surface acoustic wave device has an input interdigital transducer (IDT) and an output IDT on a piezoelectric substrate, wherein when a crossing width of an electrode finger of one IDT is denoted by X, the other IDT is divided into two IDTs each having an electrode finger having a crossing width set to substantially X/2, and the electrodes of the divided IDTs become balance output terminal pairs respectively. The divided IDTs are disposed so that the divided IDTs have a different phase at 180°with respect to non-divided IDT. Also, the common electrode width of the divided IDTs has a flat shape, having an electrode width two times larger than the pitch of the electrode finger in the divided IDTs, and the divided IDTs are connected serially by this common electrode. Further, the common electrode is connected to the ground potential. COPYRIGHT: (C)2004,JPO
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