FAST灵敏度优化及“回照”方式分析  

Optimization of Sensitivity and Back-illumination Technique for the FAST Telescope

作　　者：王君[1,2] 伍洋[2] 金乘进[2] 陈世国[1] 

机构地区：[1]贵州师范大学物理与电子科学学院,贵州贵阳550025 [2]中国科学院国家天文台,北京100012

出　　处：《电子科技》2017年第6期13-15,20,共4页Electronic Science and Technology

基　　金：国家重点基础研究发展计划(973计划)(2012CB821800)

摘　　要：针对500 m口径球面射电望远镜的灵敏度优化和天顶角超过26.4°时溢损增大引起系统噪声温度上升的问题。文中采用调整馈源照明进行灵敏度优化,提出"回照"方式降低系统噪声管温度的方法。当馈源为高斯照明时,边缘照明约为-12^-14 d B时点源观测的灵敏度达到极大值。在天顶角为30°、35°和40°时,分别选取最佳回照角为15°、21°和26°时,望远镜的灵敏度分别提高了19%、48%和100%。An optimization of the sensitivity of FAST telescope is carried out by adjusting the edge taper of a feed with Gaussian illumination. An edge taper of - 12 - - 14 dB gives the maximum sensitivity. While the zenith angle is beyond 26.4 degrees, a ＂back - illumination＂ technique is proposed to reduce the system noise temperature and optimize the sensitivity. The sensitivity is increased by 19%, 48% and 100% if a back - illumination angle of 15, 21 and 26 degrees is chosen for zenith angle of 30, 35 and 40 degrees, respectively.

关 键 词：FAST 远场方向图 灵敏度 系统噪声温度 “回照” 

分 类 号：TN822.4[电子电信—信息与通信工程]