This paper reviews some of the most relevant recent patents on waveguide orthomode transducers whose electrical function is to combine or separate two orthogonal polarisations. Different technical solutions are presented with special focus on compactness and/or improved performances. Increased power handling, reduced higher order modes generation, wide frequency band operation, etc. are some of the typical improvements targeted by the presented designs. Most of the solutions can be adapted from dual linear to dual circular polarisation operation with limited design modifications. Some of the discussed solutions can also be adapted into orthomode junctions when multiple frequency band operation is required.
Orthomode transducer, orthomode junction, waveguide, turnstile junction, dual polarisation
Antenna and Sub -Millimetre Wave Section, European Space Agency, ESA/ESTEC, Keplerlaan 1 - P.O. Box 299 - 2200 AG Noordwijk ZH - The Netherlands.