Sentinel-1 SAR Antenna Subsystem: Antenna model predictions vs. PNFS measurements

The C-SAR Antenna Subsystem (SAS) of the European Radar Observatory Sentinel-1 is an active dual-polarized phased array consisting of 280 waveguide subarrays for each polarization. In this paper, the Sentinel-1 SAS RF-pattern test philosophy in conjunction with a dedicated Antenna Model used allowing the computation of the far field pattern shapes assigned to the various SAR operational modes designed specifically for the Sentinel-1 mission (e.g. Stripmap, ScanSAR etc.) is presented,. These calculations are primarily based on embedded subarray near field measurements (active element pattern) serving as inputs to the Antenna Model. Due to the high flexibility of the Antenna Model, it is also highly attractive for other spaceborne SAR missions to come. The excellent agreement observed between the Antenna Model prediction and the pattern data acquired with the Planar Near Field Scanner Facility (PNFS) located at EADS Astrium GmbH, Germany is reported next.