Quadrature rader apparatus

Disclosed herein is a quadrature radar apparatus. In the quadrature radar apparatus, a quadrature signal generating unit generates four signals having 0 degree, - 90 degrees, -180 degrees, and -270 degrees, respectively. First and second coupler modules are connected to the quadrature signal generating unit to receive a signal and output a transmission signal and a transmission leakage signal. An antenna unit receives the transmission signal from the first and second coupler modules and a reception signal reflected from a target. A first phase delay module is connected between the first coupler module and the antenna unit to delay phases of the transmission and reception signals by 90 degrees. A leakage signal cancelling unit combines the reception signals inputted from the antenna unit through the first and second coupler modules and removes the transmission leakage signal. A power distribution unit distributes an output signal of the leakage signal cancelling unit. First and second mixing units mix the signal of the quadrature signal generating unit and the output signal of the power distribution unit.