A miniaturised X-band T/R-module for SAR-systems based on active phased array techniques

For satellite synthetic aperture radar (SAR) based on active phased array technique a Transmit/Receive (T/R) module has been developed. The T/R module operates in X-band and is capable of operating in two orthogonal polarisations alternatively. The T/R module which is described operates from 8 GHz to 10 GHz. It provides 4.0 Watts of output power and has an overall noise figure of about 3.9 dB. For phase setting a 6 bit phase shifter is implemented. The magnitude is controlled by a variable gain amplifier (VGA) with more then 30 dB dynamic range. Especially for space applications low mass is required. Therefore new technologies like multilayer ceramic carrier, highly integrated GaAs microwave monolithic integrated circuits (MMICs) and silicon control circuits in chip form (e.g. ASIC) are used for minimum size (20 mm/spl times/30 mm/spl times/70 mm) and weight of only 67 g.