Novel Double-Ridged Waveguide Orthomode Transducer for mm-Wave Application

This letter presents our study on a millimeter wave (mm-wave) orthomode transducer (OMT) based on novel double-ridged waveguide junction. By reducing the length of ridges in the square waveguide, the ridge width of proposed junction is about three times wider than that of conventional junction. This benefits the fabrication and mechanical performance of double-ridged waveguide OMT in the higher mm-waveband or terahertz band. The simulated reflection coefficients for both orthogonal modes are less than -20 dB over 37% bandwidth. As practical application, an E-band OMT based on the novel junction is fabricated. A smooth-horn is integrated with the OMT as a dual-polarized antenna. The measured results show that reflection coefficients less than -15 dB, isolation better than 39 dB, and cross-polarization discrimination (XPD) higher than 23 dB are achieved from 71 to 86 GHz.