Transmit-receiver switch

Abstract

A transmit-receive switch which can be integrated. The receive diplexer of the switch comprises a parallel resonant circuit which can be completed or connected into the switch via a heterobipolar transistor. The transmit diplexer includes a series resonant circuit or a parallel resonant circuit which is connected into the switch circuit via a further heterobipolar transistor. Each of the heterobipolar transistors is rendered conductive or non-conductive via the applied HF power. That is, a high HF power, as is present in the transmission case, causes the respective transistor to become conductive and via the respective resonant circuits, cause the receive diplexer to become high impedance and block any signal, and cause the transmit diplexer to become low impedance and pass the high HF power substantially undampened. Conversely if the power is low, as is present in the reception case, the respective transistors become blocking and via the respective resonant circuits cause the receiver diplexer to become low impedance and conduct the received energy substantially undampened to a receiver, and cause the transmit diplexer to block the passage of the received power to a transmitter.