Space-Time Coding Conformal Metasurfaces for Multifrequency Beam Steering and Shaping.

Space-time coding metasurfaces enable dynamic control of electromagnetic waves by jointly exploiting spatial coding and temporal modulation, unlocking functionalities unattainable with static platforms. While these concepts have been widely explored in planar configurations, their extension to conformal geometries has received comparatively little attention, despite the prevalence of curved platforms in practical applications. Here, space-time coding conformal metasurfaces are examined as a platform for multifrequency beam steering and shaping on nonplanar structures. A representative cylindrical geometry, characterized by translational invariance of the supporting structure along one direction and mild curvature along the orthogonal transverse coordinate, is adopted as a physically relevant configuration that enables accessible modeling of curvature effects. The proposed design strategy combines semi-analytical modeling with hybrid synthesis techniques, including evolutionary optimization. The resulting responses are validated through experimental measurements on an X-band conformal prototype employing a segmented architecture that enables controlled cylindrical bending, showing good agreement with theoretical predictions. These results demonstrate that multifrequency beam steering and shaping can be achieved on curved surfaces, establishing space-time coding as a viable and scalable approach for dynamic wave manipulation in realistic conformal environments.