低散射目标支撑金属支架的外形参数优化

低散射金属支架用于电磁散射测量中的目标支撑，是隐身飞行器设计制造过程中的重要装备。合适的支架外形可以降低自身电磁散射及变形，对于减小测量误差十分重要。通过理论计算、软件仿真、紧缩场测量的方法，从尖劈边缘绕射和行波散射的角度分析了金属支架外形参数对支架散射的影响机理，并考虑了支架变形带来的背景对消误差。在理论分析基础上，通过建立三维参数模型利用FEKO软件优化的方法，获得了工作在C频段和X频段下金属支架的最优散射倾角和截面形状，并比较了其力学变形的优劣，综合考虑散射性能和力学性能得到优化结果。提出了60°的最优倾角和70°的重载目标用倾角，以及一个后部长度占全长26.9%的非对称卵形优化截面，该截面形状可均衡降低支架垂直极化和水平极化方向的电磁散射。给出了倾角变化下尖劈绕射和行波散射变化趋势不同决定了存在优化倾角的结论，和支架前劈夹角和照明区截面长度尽量同时减小的低散射截面设计原则。研究成果对低散射金属支架设计工程化和降低电磁散射测量误差具有重要意义。

Shape optimization of target support low-scattering metal pylons.

Low-scattering metal pylon for target supporting is of great importance in the electromagnetic scattering measurement for stealth aircraft design and manufacture. The proper shape parameters can reduce the pylon scattering and its deformation,which is very important to decrease the measurement error. Through theoretical calculating,software simulation and compact range measurements,the relationships between the metal pylon shape parameters and the pylon scattering are analyzed according to the edge diffraction and traveling wave scattering theories. Based on the theoretical analysis,the 3D models with variable parameters for optimization are created in FEKO software and finally the optimum pylon tilt angle and cross section are obtained for the pylon working in C-band and X-band. The comparison of the mechanical deformation is also considered,so the optimization is achieved according to both the scattering and mechanical performance. The recommended tilt angle of 60° is selected as the optimum tilt angle,and 70° for the heavy-load pylon. An optimum asymmetric ogival cross section whose length of the back part is 26.9% of the total length is raised and it can keep reducing the pylon scattering both in the vertical polarization and the horizontal polarization in balance. The conclusion that difference between the edge diffraction edge and traveling wave scattering trends with the varying pylon tilt angle determines that there should be an optimum tilt angle is drawn. A design principle for the optimum pylon cross section is raised that both the leading edge wedge angle and the length of the cross section in the illumination zone should be reduced simultaneously. The work is of great importance in the engineering design of low-scattering metal pylon and reducing the error of the electromagnetic scattering measurements.