毫米波综合孔径辐射计近场成像研究

Research on Near Field Imaging for Millimeter Wave Synthetic Aperture Radiometer

毫米波综合孔径成像辐射计通过小口径天线构成的天线阵来探测目标场景的毫米波辐射信号,然后再利用两个天线的复相关运算来得到该目标场景的互相关函数,从而反演得到目标场景的亮温分布图像。但由于受到近场球面波的影响,近场情况下的综合孔径成像原理改变,基于远场近似条件的传统综合孔径成像方法已不再适于对近场综合孔径进行准确的图像反演。因此本文针对近场综合孔径的成像特性开展毫米波综合孔径近场成像技术研究,确立适于近场综合孔径成像的成像方法。实验结果表明,相比于传统成像方法,基于仿真结果的相位校正近场反演成像方法能有效减少成像误差。

The millimeter wave synthetic aperture imaging radiometer measures the millimeter wave radiation signal of the target scene through the antenna array composed of small aperture antennas,and then obtains the visibility function of the scene through the complex correlation operation between two array elements,and reverses the brightness temperature distribution image of the target scene.However,due to the influence of near-field spherical wave,the imaging mechanism of synthetic aperture in near-field has changed.The traditional synthetic aperture imaging method based on far-field approximation is no longer suitable for accurate image inversion of near-field synthetic aperture.Therefore,the millimeter wave synthetic aperture near-field imaging technology is studied according to the imaging characteristics of the near-field synthetic aperture,and the imaging method suitable for the near-field synthetic aperture imaging is established.The experimental results show that compared with the traditional imaging method,the phase correction near-field inversion imaging method based on simulation results can effectively reduce the imaging error.