RF Design of Dual Gimbal Antenna

摘要

This paper describes RF design and test results of a broadband circularly polarized planar array antenna and a RF non contact rotary joint operating at X-band. Planar array antenna and rotary joints are used in Dual Gimbal Antenna (DGA) System of Cartosat-2 series spacecrafts for transmitting the image information to the intended ground station. The antenna position is controlled by DGA mechanism and it points the antenna main beam towards ground station. Broad bandwidth in terms of return loss, axial ratio, and gain has been achieved in microstrip patch array using a technique called sequential rotation. High gain (22 dBi) array has been developed in light weight configuration with weight of 150g. New type of RF non contact type coaxial rotary joint has been developed with excellent electrical performance. After successfully completing all space qualification process, the DGA system has flown in Cartosat-2 spacecraft. On-orbit RF performance of the DGA system is satisfactory.