| 摘要 |
A surface acoustic wave (SAW) filter includes a piezoelectric substrate (100), a first interdigital transducer (IDT) for input (5, 6) and a second IDT for output (4) that are provided on the piezoelectric substrate (100), the first IDT and the second IDT being arranged in a propagation direction, and a shield electrode (12) arranged between the first IDT and the second IDT and/or between interconnection lines that connect the first IDT and the second IDT, at least one of the first IDT and the second IDT being of a longitudinal coupling multi-mode type having a balanced operation. Thus, it is possible to suppress a stray capacitance between the first IDT and the second IDT, and thereby to improve the symmetry of balanced operation signals.
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