Patent attributes
A branching 1 filter has an antenna terminal 3 which receives signal waves and disturbance waves, a transmission filter 11 which is connected to the antenna terminal 3, a reception filter 13 which is connected to the antenna terminal 3 and receives a portion of the signal waves and has, as a passband, a frequency range higher than a passband of the transmission filter 11, and a disturbance wave resonator which is connected to the antenna terminal 3 and to the ground and positioned closer to the antenna terminal 3 side than the transmission filter 11 and the reception filter 13. The disturbance wave resonator 15 is connected to antenna terminal 3 at a position closer to the antenna terminal 3 side than the transmission filter 11 and the reception filter 13. A resonance frequency of the disturbance wave resonator 15 is within a frequency range smaller than the passband of the transmission filter and includes a frequency range of the disturbance waves.
