| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave device that reduces an insertion loss by suppressing small ripples in a passband. SOLUTION: A surface acoustic wave element 14 has n electrode fingers for ground between electrode fingers for a signal at both ends of a central IDT electrode 3 and electrode fingers for a signal at the ends on the IDT electrode 3 sides of the IDT electrodes 2 and 4, wherein polarities of adjacent electrode fingers between the IDT electrodes are symmetrical with respect to the IDT electrode 3. A surface acoustic wave element 15 has (n-1) electrode fingers for ground between electrode fingers for a signal at one end of the central IDT electrode 6 and electrode fingers for a signal at the end on one end side of an IDT electrode 5 and has (n+1) electrode fingers for ground between electrode fingers for a signal on the other end of the IDT electrode 6 and electrode fingers for a signal at an end on the other end side of an IDT electrode 7, wherein the polarities of adjacent electrode fingers between the IDT electrodes are symmetrical with respect to the centers C and D of gaps between electrode fingers between the IDT electrodes. Electrode finger pitches of the IDT electrodes are symmetrical with respect to the center E of a gap between central electrode fingers of the IDT electrode 6. COPYRIGHT: (C)2008,JPO&INPIT
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