Near-Field Spot Beam Focusing for Multiuser Communication Using Holographic Antennas: Experiment

This companion article presents the design, characterization, and experimental validation of near-field spot beam focusing (SBF) using holographic antennas for multiuser communication. Building upon the theoretical framework established in Part I [13], we investigate key beam-focusing properties of practical holographic surfaces, including the depth of focus (DOF), angular beamwidth, focal quality, and influence of surface impedance quantization. Multiple holographic antenna prototypes are designed and fabricated to evaluate near-field SBF performance across single-user and multiuser scenarios. We further implement an interference mitigation technique based on orthogonal focal-plane beam patterns and assess its effectiveness using full-wave electromagnetic (EM) simulations and near-field measurements. The results confirm the feasibility of precise near-field beam control using holographic apertures and highlight their potential for 6G applications, such as secure communication, wireless power transfer (WPT), and short-range sensing. © 2026 IEEE. All rights reserved, including rights for text and.