A Compact Terahertz Multibeam Antenna Based on a Multimode Waveguide Beamforming Structure

In this letter, a fully metallic terahertz (THz) multimode-waveguide-based multibeam antenna operating at the band from 410 to 480 GHz is proposed. The antenna is composed of four waveguide feeders, a multimode waveguide beamforming network, four grooved waveguide phasers and a flare radiation aperture. It is realized by using high-precision Computer Numerical Control (CNC) machining technology. The measured results demonstrate that the reflection coefficients of all feeding ports are below -10 dB across the operating band. Multiple beams at the scanning range of ±32° are obtained with a scan loss less than 2 dB at 425 GHz. Wideband radiation characteristics with a maximum gain above 15 dBi and a gain fluctuation below 3 dB are realized from 410 to 480 GHz. The measured and simulated results agree very well. The antenna offers a compact and easy to implement solution for THz frequencies.