ELASTIC WAVE FILTER DEVICE

摘要

There is provided an acoustic wave filter apparatus that is allowed to improve the balancing and reduce the insertion loss in a structure where first and second acoustic wave filter sections are formed on one piezoelectric substrate, first balanced terminals of the first and second acoustic wave filter sections are commonly coupled to each other, and second balanced terminals thereof are commonly coupled to each other. An acoustic wave filter apparatus (1) where first balanced input/output terminals of first and second acoustic wave filter sections (3 and 4) are commonly connected to each other and then connected to a first balanced terminal (7), second balanced input/output terminals thereof are commonly connected to each other and then connected to a second balanced terminal (8), the first and second balanced output terminals of the first acoustic wave filter section (3) are connected to first and third acoustic wave resonators (12 and 13), respectively, via first and third wiring lines (31 and 33), respectively, and then coupled to the first and second balanced terminals (7 and 8), respectively, via the first and third acoustic wave resonators (12 and 13), respectively, the first and second balanced output terminals of the second acoustic wave filter section (4) are coupled to the first and second balanced terminals (7 and 8), respectively, via second and fourth wiring line (32 and 34) and second and fourth acoustic wave resonators (16 and 18), respectively, and the second wiring line (32) and second wiring line (33) cross each other on a piezoelectric substrate (2).