Diagnostics of the SMOS Radiometer Antenna System at the DTU-ESA Spherical Near-Field Antenna Test Facility

The recently developed Spherical Wave Expansion-to-Plane Wave Expansion (SWE-to-PWE) antenna diagnostics technique is employed in an investigation of the antenna system in the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) for ESA´s Soil Moisture and Ocean Salinity (SMOS) mission. The SWE-to-PWE antenna diagnostics technique successfully identifies the sources of the anomalies detected in 2 of the 138 MIRAS antenna far- field patterns that were measured during the on-ground calibration at the DTU-ESA Spherical Near-Field Antenna Test Facility in 2006. In addition to its obvious value for the SMOS mission, this investigation also provides an experimental validation of the SWE-to-PWE antenna diagnostics technique.