S-band electronically scanned active phased array antenna

An S-band electronically scanned active phased array antenna, with a figure of merit of 10 dB/K, is designed to receive telemetry within the frequency band from 2.2-2.4 GHz. It provides 24 simultaneous beams and covers a scan volume of /spl plusmn/60/spl deg/ in azimuth and /spl plusmn/40/spl deg/ in elevation. Sixteen of the beams are used for receiving telemetry and the other 8 for direction finding. This paper describes a couple of the key design features of the antenna system. The first feature is a highly integrated active subarray, which is implemented based on multi-layer printed circuit board and surface mount technology. The second key feature is a distributed beamforming architecture, comprising 128 integrated subarrays, 24 panel beamformer modules and 24 adaptive true time delay beamformers. This architecture is designed with an objective to reduce the hardware count by more than 50%. Hence the total cost of manufacturing, testing and calibration is significantly reduced. To facilitate telemetry acquisition and tracking, the antenna system also features a high performance direction finding system, which is implemented based on 8 correlative receivers working in parallel. Test results on the integrated subarray and correlative receiver are presented.