Branching filter

A branching filter comprising:

• an antenna terminal;
• a transmission signal terminal;
• first and second reception balanced signal terminals;
• a wiring substrate including first and second main surfaces;
• a ladder elastic wave filter chip mounted on the first main surface of the wiring substrate and including a first piezoelectric substrate and a ladder elastic wave filter that is provided on the first piezoelectric substrate, the ladder elastic wave filter chip being connected between the antenna terminal and the transmission signal terminal;
• and
• a longitudinally-coupled-resonator-type elastic wave filter chip mounted on the first main surface of the wiring substrate;
• wherein
• the wiring substrate includes an antenna back-surface electrode provided on the second main surface and connected to the antenna terminal, and a first wiring connected to the antenna back-surface electrode;
• the longitudinally-coupled-resonator-type elastic wave filter chip includes:
• a second piezoelectric substrate;
• a longitudinally-coupled-resonator-type elastic wave filter provided on the second piezoelectric substrate, connected between the antenna terminal and the first and second reception balanced signal terminals, and being configured to have a balanced-unbalanced transformation function;
• an antenna electrode pad provided on the second piezoelectric substrate and connected to the antenna back-surface electrode through the first wiring;
• and
• a second wiring provided on the second piezoelectric substrate and connecting the antenna electrode pad and the longitudinally-coupled-resonator-type elastic wave filter;
• the longitudinally-coupled-resonator-type elastic wave filter includes a first functional electrode that is connected between the second wiring and the first reception balanced signal terminal and a second functional electrode that is connected between the second wiring and the second reception balanced signal terminal;
• the second wiring extends in a first direction, and the first functional electrode and the second functional electrode are axisymmetrically arranged with respect to each other about a central axis that extends in the first direction of the second wiring;
• and
• the ladder elastic wave filter chip has a long narrow shape with a longitudinal direction that is parallel or substantially parallel to a second direction perpendicular or substantially perpendicular to the first direction.