US Patent 7756486 Transmitter and receiver impedance control using shunt switches

Circuits, methods, and apparatus that provide isolation between receive and transmit circuits in a wireless transceiver. One example provides switches that can be included on an integrated circuit with at least portions of a wireless transceiver. These switches vary the impedance of transmitter and receiver circuits between a termination impedance and a high impedance by inserting or removing components in parallel with matching networks. Signal losses are minimized since these switches are shunt connected to input and output paths on the wireless circuit and are not connected directly in either signal path.