Sub-Terahertz Metallic Multibeam Antenna Based on Sliding Aperture Technique

This paper presents a fully metallic waveguide-based multibeam antenna operating at the band from 410 to 480 GHz. The multibeam function is achieved based on the sliding aperture technique. The antenna is composed of a beamforming network based on self-compensating waveguide phase shifters, a parallel plate waveguide (PPW) and seven waveguide feeders. Each self-compensating phase shifter is realized by equal-length widened-and-grooved waveguide sections with low-dispersion phase delay, which ensures a wide operating band. The design method of the beamforming network and the phase shifter is detailed. A prototype is manufactured using high-precision computer numerical control (CNC) machining and experimentally verified on S-parameters and radiation performances. The measured results show good impedance matching at all ports and low mutual couplings between them. The achieved beam scanning ranges within the band from 410 to 480 GHz are wider than ±30° with scan losses lower than 2.5 dB. The excellent agreement between the measured and simulated results verifies the design approach and the manufacture technique. This work demonstrates a practical solution to sub-terahertz passive multibeam antenna with a robust and reliable metallic structure.