静止轨道实孔径微波天线主反热控方案研究

Research of Real Aperture Microwave Antenna Main Reflector Thermal Control Measures on Geostationary Earth Orbit

为减小静止轨道高频率、大口径微波天线热变形,提高天线的指向精度,对国内外天线主反射材料和热控方案进行了分析,发现其材料较一致选用碳纤维蒙皮/碳纤维蜂窝夹层,主反表面涂覆合适吸发比的真空沉积铝(VDA)/Al2O3(SiOx)涂层,一方面保证天线电性能对反射率大于99.8%的需求,另一方面使天线整面在轨温度梯度和波动较小。建立口径5m天线的热仿真模型,分析了三种不同吸发比涂层的天线在不同典型工况下的温度场分布,结果表明采用涂层吸发比0.2/0.2的主反热变形较小。以碳纤维材料为基体,用真空蒸镀沉积的方法在其表面镀制不同厚度的银层和二氧化硅层,制备出吸发比约0.2/0.2的VDA/SiO2热控涂层,可用于形状较复杂的曲面,且涂层的发射率随保护层厚度可调,显著提高了热控设计的灵活性。

In order to reduce the thermal distortion of high-frequency and large caliber microwave antenna and improve the directional precision,the study of main reflector material and thermal control measures in domestic and abroad was carried.It found that the carbon fiber reinforcement plastic/carbon fiber reinforcement plastic honeycomb was selected as the main reflector material and the main reflector was covered with vacuum deposit aluminum(VDA)/Al2O3(SiOx)to make the reflectivity higher than 99.8% and satisfy the electrical performance and to make the main reflector have less temperature grads and fluctuation.Thermal simulation model of main reflector with 5m was set.Temperature fields with three different ratios of solar absorption and emissivity of the coat under various operation modes were analyzed.The results showed that the thermal distortion could be less when the main reflector surface was covered with 0.2/0.2ratio of solar absorption and emissivity of the coat.The VDA/SiO2 metallic layer on CFRP surface was manufactured and the anticipant the ratio of solar absorption and emissivity(0.2/0.2)was obtained.The coat can be applied on complex curved surface and the emissivity of the coat can be adjusted according to the coat thickness,which is benefit to the design flexibility of thermal control.