Sequentially rotated microstrip array antenna at X-band for spacecraft

This paper describes design, development and test results of a broadband, light weight circularly polarized microstrip array antenna. Sequential rotation technique has been applied on the array to obtain broad bandwidth in return loss and axial ratio performance. Circularly polarized truncated corner square microstrip patch is selected as a basic radiating element in this 64 element array. The antenna array has been developed for data transmission application from Low Earth Orbiting spacecraft to the ground station. Microstrip patches and feeding network have been designed on a single microwave substrate to obtain light weight antenna. Microstrip patch, feed network, and the complete array have been analyzed on Ansoft Ensemble software. Developed array exhibits good radiation patterns, axial ratio, and return loss over required band of frequencies (8.0 - 8.4 GHz). After successfully completing all space qualification process, the array has flown in Cartosat-2 spacecraft (Indian Remote Sensing Satellite). The on-orbit performance of the array is satisfactory and matching with the ground test values.