A dual-band LFM-CW radar scheme which is based on photonic stretch processing is proposed. The receiver which is based on a photonic frequency down-converter is able to receive the radar echoes of two bands with a single hardware. A dual polarization quadrature phase shift keying modulator is employed to implement the modulation scheme. The reference signals and echoes of two bands are modulated to orthogonally polarized light waves and sent to a Pol-demux coherent receiver through an amplifier and a filter, respectively, to perform stretch processing. In the transmitter, the reference and transmitted LFM signals with high frequency and wide bandwidth are generated by a photonic-assisted frequency multiplication module. Meanwhile, the generated signal is delayed before transmission. Thus, at the output of the coherent receiver, IF signals corresponding to two bands can be separated in the frequency domain. An experimental system operating in C- and Ku-bands with transmitting signal bandwidths of 1 and 2 GHz, respectively, is demonstrated and evaluated via a series of inverse synthetic aperture radar imaging tests, and the sampling rate of analog to digital converters is 100 MSa/s. The results show that the microwave photonics technology can provide solutions for receiving dual-band signal with a single hardware platform.%该文提出一种基于光子辅助去调频接收技术的双波段线性调频连续波雷达方案，该双波段雷达接收机基于平行架构光子混频器，能够利用同一套硬件设备同时接收双波段雷达的回波信号。接收机中使用一个双偏振正交相移键控(DP-QPSK)调制器，工作中将双波段雷达的两组参考信号和回波信号通过DP-QPSK调制器调制到正交偏振的光载波上，调制后的双带光回波和参考信号经过放大和滤波后，输入到偏振解复用相干接收机中进行光子辅助去调频处理。在发射机端，对于具有更高频率和带宽的发射信号，采用包含延时功能的光子倍频信号产生技术，产生参考信号与发射信号的同时，将发射信号延时，使得在接收机端对相同距离目标的双带回波信号去调频得到的中频信号可在频域分离。实验中通过逆合成孔径雷达成像实验评估了该双波段雷达系统的性能，该双波段雷达系统工作在C波段和Ku波段，发射信号带宽分别为1 GHz和2 GHz，接收机模拟-数字转换器的采样率为100 MSa/s。实验结果证明微波光子技术能为双波段线性调频连续波雷达提供有效的实现方案。
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