Quasi optical triplexing feed for AMSU-B radiometer

Describes the triplexing feed for the AMSU-B satellite-borne radiometer which was designed using quasi-optic methods. This radiometer has been produced for the UK Meteorological Office and works in three bands around 89 GHz, 150 GHz and 183 GHz for the measurement of atmospheric water vapour profiles. The problem of triplexing 89 GHz, 150 GHz and 183 GHz channels within a restricted volume has been solved using a quasi-optical feed. This feed uses ellipsoidal mirrors for focusing, drilled plate filters for frequency separation and corrugated horn feeds. It was designed using Gaussian mode concepts supported by a full physical optics diffraction analysis. A loss requirement of 1 dB is easily met