S/Ka Band High Efficiency TT&C Reflector Antenna Design And Implementation

With the development of science and technology,there are lots of new technology spring up in the field of reflector antenna.Accompanied with the developement of communication technology,Symmetrical dual-reflector antenna is used extensively in a range of satellite communication,telemetry and telecommand control(TT&C)system,radar,and radio astronomy,especially in the field of TT&C system.In order to tacing the spacecraft,obtain the information of the angle,distance,and velocity,control the running situation of the spacecraft,the fine tracing is essential.The reflector antenna which has high gain and pointing beam is used to realized all the functions aboved,no matter in Tx or Rx.This thesis is based on the development trend of the reflector antenna.In the application background of the traditional parabolic antenna,this research use the Ka/S dual-band feed and modified ring-focus reflector as a designing scheme.For the feed,a special miniaturization and light-weight design was used to reduce the weight,volume,heat capacity,and the insertion loss.The result improves the efficiency of the G/T value of antenna system and promotes the capacity of antenna.The main job of this paper is focused on the following contents:Firstly,this thesis investigated the current situation and tendency of reflector antenna in a global scope,introduced the performance and system composition of the Ka/S dual-band feed.And then,the technology scheme of the minimized compact design for a dual-frequency band application was proposed.Secondly,some microwave devices of feed were designed independently.In the meantime,the calculation,simulation,optimization,and the detailed tests were implemented respectively.The method of using the feed which consist of S-band coaxial multimode horn and Ka-band variable flare angle multimode horn ensured a good antenna directional pattern for the feed pattern of two frequency bands and reduced the volume of the feed.The Ka-band corrugated circular polarizer has been modified and the optimal performance such as relative bandwidth and axial ratio have been achieved.With the optimization design of S-band reflective type TE21 mode coupler,the length of reflective type TE21 mode coupler was shorten to half.The combination of stripline magic Tee and stripline 90°hybrid in the S-band sum branchnetworknot only compacted the synthetic net but also solved the power capability problem.Thirdly,a microwave darkroom feed test and a far field test range were accomplished to the feed.The analyzed data and comparison results show that the theory and practical results matched well.The conclusion of this thesis demonstrates that the novel compact Ka/S dual-band feed design is necessary and feasible.Cooperating with the shaped ring-focus reflector,the antenna could qualified not only the performance of high-directivity and low-side lobe,but also functions of receiving,sending,and tracing the multi-channel circular polarization both in Ka and S band,which quite satisfactory engineering requirements.