A high-performance compact WR-4 orthomode transducer for wideband communications

Abstract This paper presents the design, fabrication and performance evaluation of a compact orthomode transducer (OMT) optimized for wideband communications. The OMT developed in this work features a circular waveguide as its common port, ensuring direct compatibility with receivers such as horn antennas, meanwhile enabling dual-polarization capabilities. The operational frequency spectrum of the OMT spans the entire WR-4 band (170 GHz–260 GHz), achieving reflection coefficients surpassing 20 dB and port isolation better than 60 dB, as validated through electromagnetic simulations. To evaluate performance of the fabricated OMT in a practical dual-polarization system, the OMT is utilized as the feed source for a horn antenna to realize a dual-polarized horn antenna system. The results demonstrate that the antenna incorporating the OMT exhibits superior performance, with average reflection coefficients close to 25 dB and port isolation exceeding 40 dB for overall operational band. These results indicate that the OMT developed in this work successfully meets the demanding requirements for polarization multiplexing in wideband dual-polarized receiver systems.