ACOUSTIC WAVE FILTER

摘要

Provided is a longitudinally coupled resonator type acoustic wave filter which uses an inter-IDT resonance mode and has a lower loss. In the acoustic wave filter (100), apodizing weights are assigned to first to third IDTs (111 to 113) having narrow-pitch electrode finger portions (111A, 111B, 112A, 113A) so that an electrode finger cross width sequentially changes along the propagation direction of an acoustic wave with the exception of the narrow-pitch electrode finger portions and so that a portion positioned at the IDT end portions of the narrow-pitch electrode finger portions (111A, 111B, 112A, 113A) has the maximum electrode finger cross width.