Patent ID: 7436353

Claim:
A transmitting-receiving module of a radar system comprising: a transmitting circuit for sending an RF signal; a three terminal circulator having a first terminal connected to a transmitting-receiving antenna which transmits the RF signal sent from the transmitting circuit and receives an RF signal which is a reflected wave of the RF signal, a second terminal to which is input a signal received by the transmitting-receiving antenna, and a third terminal connected to the transmitting circuit; a first RF switch which is connected with the second terminal of the three terminal circulator and which has two outputs; a second RF switch with two inputs; an attenuator connected between one output of the first RF switch and one input of the second RF switch; and a receiving circuit connected with the output terminal of the second RF switch, wherein during radar signal transmission, the first RF switch is connected with the attenuator, the second RF switch is not connected with the attenuator; and during radar signal reception, the first RF switch is connected with the second RF switch through one of a direct connection or through a low noise amplifier.