ASAR antenna technology

The active microwave instrument (AMI) on-board the ERS satellite provides extensive C-band synthetic aperture radar images of the Earth. From 1997 onwards a new type of instrument is envisaged. The so called advanced synthetic aperture radar (ASAR) should provide images which are compatible with those from ERS but also offer enhanced flexibility in terms of beam steering and swath width. The instrument is scheduled to fly on the European Polar Platform in 1997. The author outlines the design status of the key new element in the instrument, the active antenna