用于毫米波焦面阵成像的小F数透镜焦区矢量衍射场分析

ANALYSIS OF VECTORIAL DIFFRACTION FIELD IN THE FOCAL SPACE OF A SMALL F-NUMBER LENS FOR MILLIMETER WAVE FPA IMAGING SYSTEM

采用射线追迹法和Stratton Chu衍射积分公式研究透镜像空间的矢量衍射场 ,说明了决定衍射场分布样式的口径场相位分布的确定方法 ,对双曲面透镜给出了不同入射倾角时的焦区场功率分布 ,计算结果与实验吻合 .并考察了焦区场的矢量特性 ,计算与实验在毫米波频段完成 .

By assuming that a linearly polarized plane wave was incident obliquely onto a small F-number lens, ray tracing and Stratton-Chu diffraction formula were used to calculate the vectorial diffracted field in the focal space of the lens. Phase distribution of the field over the exit surface of the lens, which determined the pattern of the diffracted field, was illustrated. The power distributions of the diffracted field in the focal plane of a hyperbolic lens were calculated for different incident angles, which agreed well with the experiments. The vectorial characteristics of the diffracted field were examined. Calculation and experiments were carried out in millimeter wavelength range.