Broad-band orthomode transducers

The design and test results of a Quad-ridged waveguide L-band orthomode transducer (OMT) for radio telescope are presented. This OMT achieves satisfactory performance using relatively short length compared with other same kind of designs. Measurements of the system in the frequency range 1–4GHz agree well with simulation results. The broad-band return loss and cross-polarization behavior is given where the OMT used is measured in conjunction with a wide-band scalar horn.