A Reflector Based Digital Beamforming Demonstrator

Abstract

In recent years a rapid development in spaceborne SAR technology can be observed. This development is driven by a wide variety of applications like the generation of highly accurate digital elevation models, the measurement of Earth surface deformation and others, with simultaneously high spatial and temporal resolution. Especially the demand of high resolution SAR imagery challenges engineers to use available technology to full capacity. An antenna concept which finds more and more promotion in the SAR community are array fed unfoldable mesh reflectors. This concept is supplemented by a trend towards digital radars, where the signal is brought to the discrete domain almost immediately after reception. This allows for new powerful SAR modes, exceeding present-day SAR overall capabilities in terms of sensitivity, resolution and swath width by two orders of magnitude. Needless to say that such innovative SAR sensors require a thorough investigation by means of dedicated concept studies. This paper presents first digital beamforming results with a reflector based multi-channel radar demonstrator. Emphasis is laid on the verification of selected beamforming techniques, which help to show the principal feasibility of digital multi-channel SAR systems.