| 摘要 |
A surface acoustic wave duplexer of the present invention comprises a first surface acoustic wave filter having a first pass frequency band, a second surface acoustic wave filter having a second pass frequency band lower than the first pass frequency band and including a series arm surface acoustic wave resonator and a parallel arm surface acoustic wave resonator, a multi-layer package substrate including first to third package substrates, electrode pads formed on the first package substrate, a first ground potential pattern formed on the second package substrate, the first ground potential pattern being connected to the electrode pads and extending to a central region of the second package substrate and a second ground potential pattern formed on the third package substrate. One end of the parallel arm surface acoustic wave resonator is connected to ground potential via the electrode pads and the first and second ground potential patterns.
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