Duplexer for simultaneous transmit and receive radar systems

An enhanced duplexer which includes a combination of high dynamic range (HDR) amplifiers and a naovel signal cancellation circuit topology. Return signals from the circulator are fed into the first HDR amplifier. A portion of the transmit signal is sampled with a directional coupler and amplified with a second HDR amplifier and then combined with the output of the first HDR amplifier using a second directional coupler. The gain and phase of the second io amplifier are adjusted so the leakage signals are canceled to enable a radar system to simultaneously transmit and receive signals to and from an antenna with increased sensitivity of operation.