Patent ID: 6525626
Filing Date: 2003-02-25
Classification: H01P,H03H

Abstract:
A duplexer comprising:a branch circuit connected to an antenna and arranged to branch to a receiving side and a transmitting side; a receiving-side LC parallel resonant filter connected to the receiving-side of said branch circuit and arranged to cause a reception signal to be passed and a transmission signal to be attenuated; a surface acoustic wave filter connected to said receiving-side LC parallel resonant filter defining a subsequent stage of said receiving-side LC parallel resonant filter and arranged to cause the reception signal to be passed and the area near the high-frequency side of the reception signal to be attenuated; and a transmitting-side LC parallel resonant filter connected to the transmitting-side of said branch circuit and arranged to cause the transmission signal to be passed and the reception signal to be attenuated; wherein said branch circuit includes a balun element.