Tunable Transmissive Metagratings Using Single Layer Cylindrical Plasma Discharges

In this paper, we propose a novel single-layer reconfigurable transmissive metagrating based on plasma discharges. Each unit-cell consists of two side-by-side core–shell cylinders, with a tunable plasma core and a high-index dielectric shell. The structure is modeled using a free-electron plasma permittivity with adjustable plasma frequency. Analytical and numerical results show that the main transmission lobe can be switched between −41°, 0° and 41° by tuning the plasma frequencies. Transmission efficiency remains above 80% at broadside and 90% in the steered direction. This tunability enables effective directional control with low reflection and high overall power efficiency.