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1.前言为应付国际卫星通信的需要逐年增加的问题,国际商用卫星通信机构考虑转向V号系统卫星来表替以前的Ⅳ号系统和Ⅳ—A号系统卫星,现已发表了标准地面站的所需性能和参数。在V号系统中,将引进4/6千兆赫频带正交极化共用的频谱复用系统。为此,要求地面站天线除过去的高效率、低噪声特性以外,还要有良好的交叉极化特性。此外,为降低与其它线路的电波干扰,还要求天线也要有良好的宽角指向特性。卫星通信地面站天线从其维修使用的方便性来考虑,使用最多的是近场卡塞格仑天线
1. Introduction In response to the year-by-year increase in the needs of international satellite communications, the International Commercial Satellite Communications Agency has considered shifting to satellite V to replace the previous satellite IV and satellite IV-A, and has published standard ground stations Required performance and parameters. In the V system, a 4/6 gigahertz band orthogonal polarization spectrum sharing system will be introduced. For this reason, the ground station antenna is required to have good cross-polarization characteristics in addition to its past high efficiency and low noise characteristics. In addition, in order to reduce the interference with other lines of radio waves, but also requires good antenna also have wide-angle pointing characteristics. Satellite communications ground station antenna from the maintenance of its ease of use to consider the most used is near field Cassegrain antenna