The TERRASAR-X active phased array antenna

TerraSAR-X is an X-band synthetic aperture radar satellite which is financed, designed, built and operated in frame of a public-private partnership between the German Aerospace Center DLR and Astrium GmbH. The TerraSAR Frontend is based on the DLR funded technology program DESA [R. Zahn et al., June 2002]. End of 2005, TerraSAR X will be launched into a circular, sun-synchronous 514 km dusk-dawn orbit. The use of an active phased array antenna allows for a wide variety of advanced SAR modes like ScanSAR or SpotlightSAR. This supports the commercial use of the radar for earth observation services and also offers through its flexibility a good experimental platform for radar scientists. The design drivers for the array are not only antenna performance but mainly the thermal stability, mass and power efficiency and cost effectiveness.