Beam-squint-free and polarization-insensitive metasurfaces designed via ultrafast design framework and extensive meta-atom library
Chromatic dispersion fundamentally limits metasurface performance by coupling beam steering to frequency, thereby constraining bandwidth and undermining practical deployment. Here, we break this limitation by introducing a fundamentally different design paradigm for metasurfaces that decouples wavefront control from frequency. Our approach is enabled by a physics-grounded parallel equivalent circuit model that directly governs dispersion at the meta-atom level, transforming achromatic metasurface synthesis from an empirical, geometry-driven process into a deterministic and scalable design problem. Using this framework, we generate a large-scale meta-atom library exceeding 100,000 candidates with systematically engineered dispersion responses. This large and diverse library allows the direct selection of meta-atoms with near-unity reflection amplitude and independently tailored phase slopes, enabling precise control of both phase and its frequency derivative. As a result, we realize metasurfaces that preserve prescribed beam deflection angles (0° and 25°) across a wide bandwidth with negligible angular dispersion. A fabricated prototype experimentally demonstrates achromatic reflection from 8.0 to 16.0 GHz, representing a broad bandwidth for dispersion-free beamforming metasurfaces. The measured results closely match full-wave simulations and theoretical predictions, validating the robustness and accuracy of the proposed framework. By establishing dispersion as a directly engineerable degree of freedom, this work redefines the design methodology of metasurfaces and unlocks a universal route toward broadband, multifunctional wavefront control, with far-reaching implications for next-generation satellite and mobile communication systems.