准光系统中椭球面反射镜面截取方法

为了改善准光学馈电网络在气象卫星中的应用效果,提出了一种应用于准光学馈电网络中新的椭球镜面截取方法,该方法能够有效降低椭球镜面产生的损耗,并减小镜面面积.椭球镜是准光学馈电网络中用于波束传输的重要器件,经过分析高斯波束传播模型发现常规截取方法设计的椭球镜会导致额外的能量损耗,影响系统整体的电气性能.针对该问题,通过建立椭球镜面传播高斯波束模型,优化了常规镜面截取方法——根据高斯波束传播至镜面对应的束腰半径将镜面作相应平移.经过仿真发现,优化后镜面边缘的最大电平从-30 d B降低到-35 d B以下,并且镜面尺寸减小10%~30%.改进的镜面设计方法更有利于系统的紧凑布局和良好的电气特性,提高了系统信噪比,能保证微弱气象信号在传输过程中的能量维持,对改善准光系统的性能有很大意义.

Study on the ellipsoidal reflector interception methods for quasi-optical systems

For quasi-optical system, in order to improve the application performance of quasi-optical system on weather satellites, a new method of intercepting ellipsoidal reflectors that can effectively reduce extra energy loss in transmission and decrease the sizes of reflectors was proposed. Ellipsoidal reflectors are important optical elements for light beam transmission in quasi-optical system. The traditional method of intercepting ellipsoidal reflectors would introduce extra energy loss which deteriorates the performance of the whole system. To solve this problem, by building a Gaussian beam transmission model, traditional method of designing ellipsoidal reflectors was improved-translating ellipsoidal reflectors according to the beam waist radius. Simulations reveal that improved method performs better than traditional method-it not only reduces the maximal electrical level from-30 dB to-35 dB but also decreases the size of mirror by 10% to 30% which will benefit the electrical performance of quasi-optical system as a whole. All in all, improved method makes for decreasing the size and increasing signal-to-noise ratio (SNR) of the whole system, which ensures energy maintenance of weak meteorological signals during transmission process and improved method is of great significance to improve the properties of the quasi-optical system.