A 3D Printed 140 GHz Multifocal Dielectric Transmitarray Antenna for 2D Mechanical Beam-Scanning

In this work, a 3D printed multifocal all-dielectric transmitarray antenna (TAA) is proposed for two-dimensional (2D) beam-scanning at 140 GHz. Taking advantage of the TAA element phase shifting by varying incident angles, the proposed TAA can meet the phase compensation requirement for the feed beams from multiple ports with different incident angles. The genetic algorithm (GA) is employed to optimise the phase distribution at the sub-terahertz band. The measured 3-dB gain bandwidths of the proposed TAA are 14.3%. By mechanically rotating the feed horn, the multifocal TAA can realise a measured peak gain of 26.6 dBi at 140 GHz with a higher gain improvement of 12 dB and a ±30° beam-scanning range and 2.1 dB scan loss in E-plane, H-plane, and D-plane (Diagonal-plane, φ = 45°). The proposed TAA demonstrates a broadband 2D mechanical beam-scanning performance in the sub-terahertz band.