Compact Design of a Transmission‐Type Reconfigurable Intelligent Surface System for Beam‐Steering Applications

Although reconfigurable intelligent surfaces (RISs) have attracted broad attention, they usually require a large scale of elements and hundreds tunable components, particularly for beam-steering applications. Herein, methodology is proposed the compact design transmission-type RIS system beam steering. The approach leverages customized horn feed equipped with gradient refractive index metalens to tailor electromagnetic fields over aperture, resulting in focused amplitude uniform phase distributions. This enables us reduce feed-RIS distance significantly decrease using only small number components while still achieving acceptable performance. investigations are carried out through theoretical studies, simulations, experiments. A prototype fabricated as an exemplary demonstration, which occupies volume 3.3λ0 × 2.6λ0 3.5λ0, including feed, contains 3 5 60 varactors. With every single element being controlled individually by simple network, beam-scanning ranges ±30° measured on E-, H-, 45°-planes, respectively. above intriguing properties, proposal can find potential applications where miniaturization, high portability, low cost required functions.