Development of a W-band Antenna for Space-borne 94 GHz Doppler Radar

The EarthCARE mission is planned to be launched in 2013. JAXA and NICT have developed a cloud profiling radar (CPR) for the EarthCARE mission to perform observation of the cloud profiles and Doppler velocity of the cloud particles. The CPR is one of the core sensors of the EarthCARE satellite and will be the first space-borne W-band radar with Doppler measurement mode. The CPR employs a light-weighted large reflector which has to assure extremely high beam pointing accuracy and high physical surface accuracy even in the severe thermal environment in orbit of around 450 km height. Therefore, the CPR antenna reflector has been designed to have quite lower thermal deformation compared to the general reflectors used for the communication satellites. This report shows preliminary design result of the CPR antenna main reflector, the measured characteristics of the reflector material, and the results of the bread board model manufacturing and testing. The results concluded the manufacturing feasibility and thermal tolerance of the reflector are almost successfully evaluated.