Sun Guanqun, Zhang Fangzheng, Pan Shilong
Opt Lett. 2021 Nov 15;46(22):5659-5662. doi: 10.1364/OL.441803.
Millimeter-level resolution through-the-wall radar (TWR) imaging is demonstrated using a broadband nonlinear frequency-modulated (NLFM) signal that is generated by an optically injected semiconductor laser. The proposed system uses period-one dynamics of a semiconductor laser, together with an optical frequency downconversion technique to generate NLFM signals, which addresses the problem of traditional period-one oscillation not being able to generate broadband signals in the low-frequency region. In the experiment, an NLFM signal having a broad bandwidth of 18.5 GHz (1.5-20 GHz) is generated with a corresponding radar range resolution of 8.1 mm. Using this signal, TWR imaging is demonstrated, in which the use of the NLFM signal achieves good side-lobe suppression during pulse compression, and a modified back projection imaging algorithm with sub-aperture weighting is proposed to improve the imaging quality.
利用由光注入半导体激光器产生的宽带非线性调频（NLFM）信号，展示了毫米级分辨率的穿墙雷达（TWR）成像。所提出的系统利用半导体激光器的一阶动力学特性，结合光频下变频技术来产生NLFM信号，解决了传统一阶振荡无法在低频区域产生宽带信号的问题。在实验中，产生了带宽为18.5 GHz（1.5 - 20 GHz）的NLFM信号，对应的雷达距离分辨率为8.1 mm。利用该信号进行了TWR成像演示，其中NLFM信号在脉冲压缩过程中实现了良好的旁瓣抑制，并提出了一种带子孔径加权的改进型背投影成像算法来提高成像质量。
