High Capacity Dual-Polarization THz-Wireless Transmission in the 300 GHz Band using a Broadband Orthomode Transducer

We report on the broadband, dual-polarized THz-wireless transmission with >100 Gb/s net data rate in the 300 GHz band, employing a new broadband orthomode transducer, which is realized by a new microstrip probe-fed circular waveguide transition. It omits the use of hybrids for the commonly used balanced 4-port excitation, and for that reason, is more suitable for a planar active integration with transceiver MMICs. Characterization of the orthomode transducer in back-to-back configuration shows very low losses of less than 1.5 dB per transition over a bandwidth of more than 40 GHz with a total back-to-back cross polarization of better than 25 dB. Constellation diagrams and signal spectra from the dual-polarized wireless transmission experiments are compared to single-polarized transmission, showing only small degradations due to cross-polarization effects. The paper demonstrates that this simplified polarization multiplexer is a potential candidate for use in a wireless extender of a coherent fiber-optical transmission system.