Patent ID: 7034635

Claim:
An antenna duplexer coupled to an antenna terminal connected to an antenna, said antenna duplexer comprising: a transmission filter receiving a transmission signal and passing a first signal having a first predetermined pass band; and a reception filter receiving a reception signal obtained from said antenna terminal and passing a second signal having a second predetermined pass band, phase-shift circuit means provided between said antenna terminal and at least one of (1) said transmission fitter adjusting a phase of said transmission filter and (2) said reception filter adjusting a phase of said reception filter, wherein an absolute value of a phase difference is in a range between about 100 degrees and about 170 degrees, inclusive, and the absolute value of the phase difference is between at least one of (1) a first phase of an impedance toward said transmission filter and a second phase of an impedance toward said reception filter, each impedance viewed from said antenna terminal and at a predetermined frequency in said first pass band, and (2) a third phase of an impedance toward said reception filter and a fourth phase of an impedance toward said transmission filter, each impedance viewed from said antenna terminal and at a predetermined frequency in said second pass band.