On Space-based Synthetic Aperture Radar Antennas

Several Space-borne Synthetic Aperture Radar (SAR) instruments have been realised. Different antenna design solutions have been selected. It is noted, that in 2007 (nearly 30 years after Seasat) four different antenna designs have been implemented. Antennas based on a reflector (SAR-Lupe) or based on active phased array are used, the latter with waveguide- (TerraSAR-X) or patch-radiators (Radarsat 2, Cosmo-Skymed). Further developments and investigations continue, also with exploitation of digital beam-forming not only for (phased) array antenna-based solutions but also possibly for implementations with feed arrays within reflector antennas.