Charging analysis of GSAT-17 patch antenna

GSAT-17 spacecraft is one of the most complicated and technologically advanced Satellites being built by Indian Space Research Organisation (ISRO). The payload configuration of GSAT-17 spacecraft is 24 channels In Normal C-Band Transponders, 12 channels in Upper Ext. C-Band Transponders, 2 Channels in Lower Extended C transponders, 2 Channels each in MSS and DRT/SAR. For Lower Ext-C band, 0.75m × 0.77m Tx./Rx. patch array (8×4) antenna is designed for both uplink and downlink signals. This antenna is mounted on EV top of the satellite and provides coverage to southern Indian peninsula and Antarctica. This poses a charging threat, if not properly grounded, due to GEO spacecraft charging. Hence a good grounding scheme is necessary for ESD compliance. A study was taken up to assess the surface and internal charging effects on the antenna and proper grounding scheme was worked out to mitigate this problem.