Highly integrated front-ends for space-based SAR

New SAR instruments for space applications are using or plan to use active front-end technologies. The advantages of active front-end are well known: high flexibility, low insertion losses, low noise figure, new SAR modes (like ScanSAR). However there are also some problem areas associated with active front-ends, e.g. the instrument stability: thousands of TR modules are use, which are inherently sensitive to temperature variations. Similar difficulties are encountered with the radiators. Further on, efficiency improvement as well as reductions in mass, volume and costs are challenges for future space radars. In Germany, at Astrium GmbH, active phased array technologies for space use have been developed since more that a decade. It was started with basic technology developments that have brought the active phased arrays to a space qualification level. These technology-developments have been performed mainly for the national authorities DLR and BWB. Remarkable progress has been achieved. This paper will describe in more detail the most important system and technology features of the recent phase array developments at Astrium GmbH.