US Patent 7629863 Filter and duplexer

A duplexer includes: a first filter that is connected to a common terminal and a first terminal, and includes a first series-arm resonator; a second filter that is connected to the common terminal and a second terminal; a first inductor that is connected in parallel to the first series-arm resonator; a mounting unit that has the first filter and the second filter mounted thereon; a first inductor line that is provided on the mounting unit, and connects the first inductor and the first series-arm resonator; and a first terminal line that is provided on the mounting unit, and connects the first filter and the first terminal. In this duplexer, the directions of currents flowing through the first inductor line and the first terminal line cross each other.