Design of Duplex Terahertz Waveguide Rotary Joint Based on Septum Polarizer

This letter describes a duplex terahertz (THz) waveguide rotary joint which is consisted of a pair of septum polarizers (SPs) placed face to face. Using SP to generate a pair of orthogonal circularly polarized signals, the rotary joint can achieve duplex transmission. For all ports, the reflection coefficients are all below -20 dB, port-to-port isolation is below 24 dB, the cross polarizations transmission coefficients are below -25 dB, and it shows stable performance at different rotation angles in the frequency from 200 GHz to 235 GHz, which can be used in future terahertz scanned antenna systems.