Circularly-polarized horn antennas for terahertz communication using differential-mode dispersion in hexagonal waveguides

In this work, we present a class of circularly polarized (CP) horns that are scalable to sub-mm-wave and terahertz bands. The presented design utilizes a hexagonal waveguide, that is hollow and can be easily fabricated in these bands, as opposed to traditionally used waveguide partitions. We demonstrate the proposed design using a WR-8 (90-140 GHz) horn showing 18 dBi gain with 37% 3dB axial-ratio (AR) bandwidth. Design-optimization, fabrication steps and measurement results are presented in the paper.