Broadband Substrate Integrated Waveguide Orthomode Transducers

Abstract

A broadband planar orthomode transducer (OMT) is implemented using substrate integrated waveguide (SIW). A square waveguide is mounted on the substrate where four SIW arms are used to separate orthogonally polarized signals. Four rectangular ridges are inserted into the square waveguide to match the impedance between the square waveguide and SIW. A SIW-to-microstrip line transition and a coaxial-to-square waveguide adaptor are designed for the measurement of the proposed OMT. The designed SIW-OMT operates over the C band covering from 3.4 GHz to 4.2 GHz, whose bandwidth is more than 25%, and measured results validate our design, concept and procedures.