Compact Ka Band Orthomode Transducer with Conical Horn Antenna

Orthomode transducers (OMTs) are essential microwave devices designed to separate or mix orthogonal modes, often using waveguide technology. This paper presents the design of a compact wideband OMT operating in the Ka band (26-40 GHz) with enhancements through a circular 20 dBi horn antenna. The OMT is designed to radiate vertical, horizontal or circular polarizations, due to its coaxial input ports and the use of a square waveguide carrying TE10 and TE01 modes. The design of the OMT incorporates a Boifot junction, optimizing the septum shape, axial port transformers, side port combination, and an innovative output configuration. The final design also includes rounding sharp edges and corners for improved manufacturing precision. The results of the simulation and measurement demonstrate the effectiveness of the design. This compact Ka band OMT with a conical horn antenna holds promise for a wide range of electromagnetic measurement applications.