Broadband Silicon‐On‐Glass Reflective Dielectric Metasurface for THz Beam Steering in 6G Wireless Networks

ABSTRACT The rapid emergence of terahertz (THz) communication technologies is driving the need for compact, low‐loss, and CMOS‐compatible beam‐steering solutions to enable high‐speed wireless links in future 6G networks. In this work, we report the first experimental demonstration of an all‐dielectric, reflective silicon‐on‐glass metasurface functioning as a phase‐engineered reflective metasurface for precise beam shaping at THz frequencies. By engineering a planar 2D array of high‐aspect‐ratio silicon pillars that exhibit loss–loss Mie resonances and leverage the refractive‐index contrast between silicon and glass, we achieve full 0 − 2π reflection‐phase control near 0.5 THz. A comprehensive parametric study reveals how unit‐cell geometry and substrate thickness influence electromagnetic response, enabling tailored phase profiles across the metasurface. Utilizing phase‐mask synthesis, we realize single‐, dual‐, and five‐beam steering functionalities, demonstrating the metasurface's versatility for multi‐user environments. Fabricated prototypes are experimentally validated in a free‐space THz link, confirming beam deflection accuracies within 1.5° and inter‐beam amplitude variation under 3 dB. The close agreement between measured and simulated results not only validates the feasibility of passive, CMOS‐compatible dielectric platforms for broadband THz beamforming, but also establishes the Silicon‐on‐Glass metasurface as a scalable low‐loss‐ solution for multi‐beam wireless communication in future THz and 6G deployments.