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

In this letter, a 3-D printed multifocal all-dielectric transmitarray antenna (TAA) is proposed for 2-D 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 optimize 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 2-D mechanical beam-scanning performance in the sub-terahertz band.