Final design and testing of the 94 GHz quasi-optical-feed for the EarthCARE´S Cloud Profiling Radar

Instruments for Earth observation working from W-Band up to mm-wave frequencies mainly use quasi-optical feed systems (QOF) to illuminate the corresponding reflector antennas. The final design of the QOF for the Cloud Profiling Radar System (CPR) for the EarthCARE satellite is presented. Such QOF achieves polarization and frequency tuning, as well as separation of transmit and receive channels. The initial design of the QOF was made by MAAS and Thomas Keating (TK) as subcontractor of Astrium GmbH. The final contractor of QOF at JAXA and ESA/ESTEC is NICT in Japan. The final design verification was performed by Astrium with QUAST, a new add-on to the GRASP software, especially developed by TICRA for a fast and accurate set-up and analysis of quasi-optical networks. Within the paper, the modeling of the QOF will be explained in detail and a description of QUAST will be given. Finally, a validation with measurement performed at the National Physical Laboratory (NPL) in UK will be provided.