A Compact 3-D Printed Asymmetric Orthogonal Mode Transducer

In this article, a compact 3-D-printed orthogonal-mode transducer (OMT) is proposed. Unlike conventional OMT that uses long extended transition for port matching, the proposed design uses embedded fences and novel short tapered triangular prism (TTP) to replace such long transition. In this way, the size of the OMT can be reduced. The TTP effectively improves the matching of the perpendicularly transverse port without affecting the performance of the port aligned with the common port. The fence acts as a polarizer grid to further reduce the reflection of incident waves back into the input port. The return loss and isolation of the very compact OMT are better than 16 and 40 dB, respectively, from 2.65 to 3.2 GHz. Considering the complicated geometry of the proposed OMT, 3-D metal printing technology is adopted as the fabrication method. The measurement results agree well with the simulation results.