A Design of Orthomode Transducer Loaded With Polarization Grid

Abstract

The Orthomode Transducer (OMT) is a widely used device in satellite communication systems, and the T-junction OMT is always a candidate for volume saving. In this study, a design of an OMT loaded with a polarization grid is proposed, based on the traditional T-junction OMT structure. Additionally, a conical horn is integrated into the presented OMT. The entire system was subjected to simulation, fabrication, and measurement. In 29.8–32.2 GHz, both the simulated and tested Voltage Standing Wave Ratio (VSWR) values for the two orthogonal ports remain below 1.2, with a measured isolation of 60–75 dB. At 31 GHz, there is a good agreement between the simulated and measured far-field patterns for the main polarization, with cross polarization levels measured at less than −15 dB. These results from both simulation and measurement validate the effectiveness of the design approach, which not only improves the isolation levels compared to the traditional T-junction OMT but also simplified the OMT’s matching design.