A Simple Asymmetric Orthomode Transducer Based on Groove Gap Waveguide
The groove gap waveguide (GGWG) technology is used to design a simple asymmetric orthomode transducer (OMT) at the Ka band in this letter. The OMT consists of two metal layers which do not need electrical contact due to the property of the gap waveguide technology. The vertical polarization (VP) is directly fed to a standard rectangular waveguide port from the main arm of a square waveguide, while the horizontal polarization (HP) is fed to the side arm by an H bend. No septum or iris is needed, which contributes to a simple structure. The OMT has been manufactured and measured using a back to back setup. A high isolation of over 40 dB is achieved within the working band from 26.1 to 29.3 GHz. The reflection coefficient is below 11.4 and 17.7 dB for the HP and VP, respectively. The higher return loss of the HP is caused mainly by the manufacturing errors. Nevertheless, the insertion loss for both polarizations is below 0.25 dB for a single OMT.
IEEE Microwave and Wireless Components Letters