Design of Wideband Asymmetric Ortho-Mode Transducer WithTwist Based Symmetrical Co-Oriented Rectangular Waveguide Ports

This paper presents a wideband orthomode transducer (OMT) with symmetrical rectangular waveguide ports.The designed OMT operates over frequency range of 10.7GHz-14.5GHz with standard rectangular waveguide ports for achieving orthogonal polarizations. The proposed OMT consists of multi section waveguide transformers, circular to rectangular waveguide transition and a 90 degree waveguide twist. Design approach with full wave EM simulations and experimental results are explained in detail. Experimental prototype shows a return loss of better than 18dB over the designed band, maximum insertion loss is 0.6dB for both ports and port isolation is better than 35dB. Experimental results are compared and discussed.