Design of Compact Orthomode Transducers

This paper presents the design of compact orthomode transducers (OMTs). Analysis methods for waveguide OMTs, including the mode-matching method and hybrid methods, are briefly reviewed. Three types of compact OMTs are described: a dielectric-filled OMT with reduced size, a planar OMT implementing using substrate integrated waveguide, and a dual band Tx/Rx OMT with a compact diaphragm to improve isolation. The dual-band Tx/Rx and SIW OMTs are verified by measurements. Challenges for designing multi-band OMTs with compact size are also pointed out.