Design of two Ku-band orthomode transducers for radio astronomy applications

Two different designs of orthomode transducers for the coming Ku-band receiver of the Italian radio telescope in Medicina are presented and compared, showing design details, describing numerical simulations and discussing manufacturing and test results. Such orthomode transducers provide a tradeoff between low-loss and phase-matching, according to different initial requirements where the final receiver architecture has to be frozen. Both designs show high performance over the operative 13.5-18.1 GHz Ku-band. One of the OMT designs has been fabricated and tested, showing results in very good agreement with simulations.