Elastic wave filter, and duplexer and electronic device using same

摘要

An elastic wave filter has first, second, and third IDT electrodes whose wiring electrodes are connected to unbalanced signal terminal; fourth IDT electrode disposed between the first and second IDT electrodes; fifth IDT electrode disposed between the second and third IDT electrodes; and first and second balanced signal terminals connected to the wiring electrodes of fourth and fifth IDT electrodes, respectively. The ground electrodes of the first through fifth IDT electrodes are connected to the ground. Signals in opposite phase and in phase with a signal input to unbalanced signal terminal are output from first and second balanced signal terminals, respectively. The wiring electrodes of second and third IDT electrodes are adjacent to the ground electrode of fifth IDT electrode. The wiring electrode of one of first and second IDT electrodes is adjacent to the wiring electrode of fourth IDT electrode. The ground electrode of the other is adjacent to the ground electrode of fourth IDT electrode. This configuration can suppress spuriousness in the bandpass.