A 3D-Printed Simple Asymmetric Orthomode Transducer for Wideband THz Applications

A novel compact asymmetric wideband orthomode transducer (OMT) design method is presented in this paper. The design employs an asymmetric geometry which is based on a T-waveguide transmission line. To address the issue of higher-order mode reflections typical of asymmetric structures, a novel T-shaped waveguide-to-waveguide transducer structure has been proposed. This new structure is compatible with both fundamental and higher-order modes, expanding the bandwidth of the OMT. To verify the design, the OMT is connected to a pyramidal horn and fabricated by micro-3D printing with a weight of only 0.35 g. Measured results demonstrate that the proposed OMT achieves a wide bandwidth of 53.9% (from 126 GHz to 219 GHz) and an isolation between the two ports of more than $\mathbf{5 0} \mathbf{d B}$. Benefitted from the compact structure and excellent performance, the new method would be an attractive candidate in the new generation of terahertz wireless communication systems.