Photonic Deramp Receiver for Dual-Band LFM-CW Radar

A photonic deramp receiver based on a photonic mixer for dual-band linear frequency-modulated continuous wave radar is proposed. In the receiver, a novel modulation scheme is developed, employing a dual polarization quadrature phase shift keying modulator which contains four sub-Mach-Zehnder modulators (sub-MZMs). The echoes and reference signal of the first band are modulated to light waves on a pair of peak-biased sub-MZMs for tracking, while the echoes and reference signal of the second band are modulated on the other pair of null-biased sub-MZMs for imaging. An experimental system, operating in C-band and Ku-band with a bandwidth of 850 and 3600 MHz, respectively, is demonstrated and evaluated via a series of inverse synthetic aperture radar imaging tests. The results verify the idea of the dual-band radar receiver, which provides a solution for receiving dual-band echo signals with a single hardware platform.