Wideband Dual Polarizations Feed For Radiometer

This paper presents the design and development of a wideband Finline orthomode transducer(OMT) and feeding system used for the radiometer. Finline OMT and filters are employed to separate the dual polarization waves for different frequencies. The wide band loaded corrugated horn is used to cover the almost 2:1 frequency band. Test results shown that the feed horn patterns at three frequencies (18.7GHz, 23.8GHz and 37GHz) remain good shape, while the cross-polarization levels are below -23dB at all working bands. The VSWR are lower than 1.5 at all the three working frequency bands.