Patent ID: 8081048

Claim:
A branching filter comprising: a first tank circuit including a tank-circuit inductor and a tank-circuit electrostatic capacitor element arranged in parallel, the first tank circuit having one coupling part coupled to a first transmitting/receiving signal terminal; a first lowpass filter having one coupling part coupled to another coupling part of the first tank circuit; a first inductor having one coupling part coupled to another coupling part of the first lowpass filter, and the first inductor having another coupling part coupled to a reference potential; a first electrostatic capacitor element having one coupling part coupled to the other coupling part of the first lowpass filter, and the first electrostatic capacitor having another coupling part coupled to a second transmitting/receiving signal terminal; a second lowpass filter having one coupling part coupled to the first transmitting/receiving signal terminal; and a second electrostatic capacitor element having one coupling part coupled to another coupling part of the second lowpass filter, and the second electrostatic capacitor having another coupling part coupled to a third transmitting/receiving signal terminal.