二维干涉式被动毫米波近场目标成像分析

Near–field imaging analysis of 2–D millimeter–wave interferometric radiometer

摘要:

近场成像是干涉式被动毫米波成像技术的重要应用领域，阵列构型是影响近场相位误差的重要因素。搭建二维合成孔径近场成像仿真系统，实现目标场景生成、近/远场前向仿真、图像重构和近场相位误差等功能。利用该系统对空间分辨力相同条件下的常用二维天线阵型的近场误差进行定量评估和分析，针对二单元的近场扫描成像试验系统，提出一种将接收机通道误差、近场相位误差分步校正的自定标方法。比较基于参考点源的近场成像方法，该方法仅需先验距离信息，无需再对参考点源进行成像，具有操作简单、成像速度快的优势。

Abstract:

Near–field imaging is an important application area of interference passive millimeter-wave imaging technology, and the array configuration is an important factor affecting the near–field phase error. In this paper, a 2–D synthetic aperture near–field imaging simulation system is built to implement functions such as target scene generation, near/far field forward simulation, image reconstruction, and near–field phase error correction. This system is utilized to quantitatively evaluate and analyze the near–field errors of different 2–D antenna arrays with the same spatial resolution. For the two–unit near–field scanning imaging test system, a self–calibration method is proposed to correct the receiver channel error and near–field phase error respectively. Compared with the near–field imaging method based on a reference point source, this method requires only a priori distance information and no need to image the reference point source, which bears the advantages of simple operation and fast imaging speed.