星载天线反射面型面热变形影响因素分析

星载天线在轨运行时受到周期性的温度变化影响，天线反射面会发生热变形，影响天线增益。热膨胀系数是描述结构热变形的重要参数，并且会随温度变化；在进行结构热变形分析时若将热膨胀系数视为常数会给仿真分析带来误差。文章以抛物面天线反射面为研究对象，考虑热膨胀系数随温度的变化，针对ULE玻璃和M55层合板材料的反射面，仿真分析反射面厚度、支撑位置、选用材料等因素对星载天线反射面型面热变形的影响。结果表明，对于抛物面天线，支撑约束在中间位置时反射面型面误差最大；采用ULE玻璃的优化方案可将型面误差减小约1个数量级。实际设计中还要综合考虑质量、刚度及模态特性。

Analysis of influencing factors on thermal deformation of satellite onboard antenna reflector

For onboard satellites, the satellite antenna is subjected to the periodic temperature change, along with the thermal deformation on the antenna reflector, and the loss of the antenna gain. The coefficient of the thermal expansion, as an important parameter to describe the thermal deformation of the structure, varies with the temperature. If the coefficient of the thermal expansion is taken as a constant in the simulation analysis of the thermal deformation, there would be non-ignorable error. In this paper, for the reflector of a parabolic antenna, with consideration of the variations of the thermal expansion coefficient against the temperature, the influences of the thickness of the reflector, the position of the support, and the selection of material on the thermal deformation of the reflector made of ULE glass and M55 laminate are simulated and analyzed. It is shown that for a parabolic antenna, the error of the reflector is the largest when the support constraint is in the center position. The optimization scheme with the ULE glass can reduce the surface error by about one order of magnitude. In the practical design, the mass, the stiffness, and the modal characteristics should be considered carefully.