| 摘要 |
PROBLEM TO BE SOLVED: To provide a balanced surface acoustic wave device with high quality that acts like a balanced type device and has an excellent filter characteristic. SOLUTION: The surface acoustic wave device S1 is configured such that resonator type electrode patterns 14 consisting of 3 IDT electrodes or more placed in parallel along the propagation direction of a surface acoustic wave are placed on a piezoelectric substrate 11, one of the 1st stage and the final stage of the resonator type electrode patterns 14 is used for a balanced input section or an unbalanced input section, and the other is used for an unbalanced output section or a balanced output section, the resonator type electrode pattern used for the unbalanced input section or the unbalanced output section is formed by placing IDT electrodes to both sides of a 1st center part IDT electrode for inter-stage connection of the resonator type electrode patterns 14 in a way of having the same phase, and the resonator type electrode pattern used for the balanced input section or the balanced output section is formed by placing IDT electrodes to both sides of a 2nd center part IDT electrode for inter-stage connection of the resonator type electrode patterns 14 in a way of having the opposite phase.
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