卡塞格伦光学天线偏轴及性能分析

Properties of Cassegrain optical antenna with inclined optical axis

设计了具有抛物面结构的卡塞格伦光学天线.通过对偏轴下的卡塞格伦光学天线系统的分析,得到了不同偏转角所对应的接收光斑面积表达式和功率衰减曲线.讨论了偏轴下的接收天线增益与波长及偏转角的关系,仿真出在偏轴与轴对准两种情形下的增益曲线.仿真结果表明,最大偏轴比轴对准情形增益降低了6.564dB.最后分别针对轴对准与某种偏轴情形下的系统做了光斑测试实验与天线耦合效率测试实验.结果为:偏轴下天线耦合效率降低了26.966%.这些研究为星间光通信中控制系统实现光轴的精确对准提供了理论依据,具有重要的实用价值.

A Cassegrain optical antenna with parabolic structure is designed. By detailed analysis of Cassegrain optical antenna in partial axis situation,the expression of the area of the receiving spot and the power decline curve are obtained for different deflection angles. The relations between the received antenna gain and the wavelength and deflection angles are discussed in partial axis situation,the curves of gain for partial axis and axis alignment are simulated. The simulation result indicates that the gain of the maximal partial axis decreases by 6.564？dB compared with that of axis alignment. Experiments of the optical spot test and the antenna coupling efficiency test are carried out separately for axis alignment and certain partial axis situations. The results show that the antenna coupling efficiency under partial axis situation is 26.97% lower than that of axis alignment. This study will provide a theoretical foundation for the control system to realise perfect alignment of optical axis in inter-satellite optical communications.