Antenna duplexer and mobile communication device using the same

摘要

An antenna duplexer has an antenna terminal; a transmitting phase-shift circuit, one side of which is connected to the antenna terminal; a receiving phase-shift circuit, one side of which is connected to the antenna terminal; a transmitting filter connected to the other side of the transmitting phase-shift circuit and a transmitting terminal; and a receiving filter connected to the other side of the receiving phase-shift circuit and a receiving terminal; wherein the transmitting filter and/or the receiving filter is a composite filter, and the composite filter attains a characteristic having an attenuation pole at simultaneous transmission and reception time when transmission and reception are simultaneously performed, and controls respective impedances by the transmitting phase-shift circuit and the receiving phase-shift circuit to operate as a sharing unit and attains a characteristic where the attenuation pole is removed at non simultaneous transmission and reception time when transmission and reception are not performed simultaneously.