LADDER TYPE FILTER AND DUPLEXER

摘要

A ladder type filter that can be reduced in size and can have low loss is provided. The ladder type filter is provided with: a piezoelectric substrate 2; an insulating film 10 disposed on the piezoelectric substrate 2; first and second IDT electrodes 3A, 3B provided on the piezoelectric substrate 2 and each having a pair of bus bars and a plurality of electrode fingers; a first wiring electrode 4, at least a section of which is provided as one of the bus bars of the first IDT electrode 3A; a second wiring electrode 5, at least a section of which is provided as one of the bus bars of the second IDT electrode 3B; and a third wiring electrode 6 layered on the second wiring electrode 5. The first wiring electrode 4 and the second wiring electrode 5 are connected to different potentials, respectively, and are separated from each other, and at least a section of the third wiring electrode 6 overlaps at least a section of the first wiring electrode 4 in the layered direction with the insulating film 10 interposed therebetween.