Design of 2X2 EMCP Fed Microstrip Patch Array For Altimeter Payload on Space Re-Entry Vehicle

This paper presents the design of X-band 2 $\times$ 2 EMCP fed microstrip array antenna designed to be placed on the outer body of the space re-entry vehicle (SRV) for radar altimeter application. This paper describes the modelling and analysis of array antenna with SRV body covered with Thermal protection system (TPS) layers; The reasons for poor isolations between transmit and receive antenna and methods to improve it. The antenna is designed & optimized using the 3D electromagnetic solver, taking effects of SRV body and TPS layers to achieve the desired performance with peak gain 10.4 dBi and return loss better than 20dB (8% bandwidth for 20dB). The antenna is also fabricated & measured. The fabricated antenna in stand-alone condition has a gain of 12.4 dBi, return loss better than 25dB and RF isolation between the transmit and receive antenna pair better than 70dB.