Patent ID: 7330500
Filing Date: 2008-02-12
Classification: H04B

Abstract:
1. A duplexer for a communication device having a transmission unit, a reception unit and a shared antenna, the duplexer comprising: a transmitter port adapted to receive a transmission signal from the transmission unit; a receiver port adapted to transmit a reception signal to the reception unit; an antenna port adapted to transmit the transmission signal to the shared antenna and receive the reception signal from the shared antenna; a first signal path between said transmitter port and said receiver port; a filter unit in said first signal path for filtering said reception signal, said filter unit causing a leakage signal to occur between said transmitter port and said receiver port; a second signal path between said transmitter port and said receiver port; and a cancellation unit in said second signal path adapted to receive a sample of the transmission signal and produce a compensation signal that is injected into the first signal path to substantially reduce the leakage signal.