Abstract: The antenna of a transceiver couples through a low pass filter to the input port of a high pass filter network. The high pass network is designed to reflect a very high impedance to its input port when its output port is at ground potential. The transmitter portion of the transceiver couples to the input port of the network with the receiver coupling to the network output port. A semiconductor diode couples from the output port to ground potential.In the receive mode the combination low pass and high pass filters couple received signals in the desired frequency band to the input of the receiver. Upon activation to the transmit mode the diode is forward biased whereby the network output port is taken to ground potential. In this mode the filter network effectively isolates the receiver from the transmitter.