| With the development of space and electronic technology,deep space exploration is paid more and more attention in global.Moon and Mars exploration will be a focus in 21st century.Chinese lunar exploration project ’Chang-E Plan’ was officially launched in 2004,construction of the Deep Space Network was commenced.Deep Space Station(DSS)received signals sent back from distant deep space,so signal level was already very weak when it reached the Earth because of loss on path.Intentional space powers tried to increase system G/T value through many measures.However,currently the antenna aperture is increased to a certain limit,then reduce noise temperature of the feed system will be an inevitable choice for this purpose.This thesis follows the trend of international DSS,apply refrigeration solution to Ka-band feed&LNA receiver in overall system.Achieved a design for Ka-band feed miniaturization and lightweight,its size,weight,thermal capacity and transmission losses were reduced.The Ka-band feed got less than 50K noise temperature via put it in 20K refrigeration environments.This solution improves the antenna system G/T value effectively.This thesis includes the following contents:First of all,the development and trends of international large-aperture antenna in DSS is researched,proposed performance and constitution of feed system in the background of DSS,and planed a refrigeration solution for Ka-band feed&LNA receiver in overall system.Second,design of three basic feed components is completed,including calculation,simulation,structure design,manufacture,installation and test of these components.Third,author tested the electrical parameters of overall system in normal and ultra-low temperature environment.Especially,system noise temperature measurement in the refrigeration environment is achieved.Calculation and comparison of these parameters show that system noise temperature reduced 27.70K,system G/T value increased 1.03dB,this is equal to antenna aperture enlarge 4.2m,reception ability of Ka-band promote 22%.The results testified that the refrigeration solution is inaccessible and feasible.The feed equipment using overall refrigeration developed in this topic is the first Ka-band feed in DSS large-diameter antenna applications of China. |
