Ultra‐Wideband Frequency Beam‐Steering Transparent Metasurface Enabled by Fine Metal Line

Abstract Optically transparent and ultra‐wideband metasurfaces are key enablers for future wireless–optical systems, offering electromagnetic functionality without compromising visible‐light transmission. In this work, a flexible and transparent beam‐steering metasurface is demonstrated, based on a three‐layer fine metal line (FML) network patterned on PET substrates with an interleaved air gap. The metasurface enables linear polarization rotation and broadband phase compensation while achieving high optical transparency (∼70%) and mechanical flexibility. The transmitarray is optimized to steer beams over a broad frequency range from 13 to 32 GHz through passive frequency‐dependent phase dispersion. Simulations and measurements confirm consistent beam deflection from 26° to 9°, with a peak gain of 26.03 dBi and stable aperture efficiency above 40%. Conformal simulations demonstrate that beam‐steering performance is maintained under bending angles up to 20°, with no degradation in optical or electromagnetic functionality. Combining with ultra‐wideband operation, transparency, conformability, and scalable fabrication, the proposed metasurface presents a promising solution for next‐generation transparent antennas, radomes, and smart wireless–photonic platforms.