A single active metasurface for arbitrary polarization control

This paper proposes a novel broadband reconfigurable polarization converter (BRPC) based on an active metasurface. The design integrates PIN diodes into the meta-atoms to allow dynamic control over the output wave polarization across multiple bands. The core innovation of our design lies in its comprehensive and polarization-insensitive reconfiguration capability: regardless of whether the incident wave is linearly polarized (LP) or circularly polarized (CP), the converter can dynamically generate reflected waves in the forms of x-polarization, y-polarization, right-hand circular polarization (RCP), or left-hand circular polarization (LCP) by switching the diode states across different frequency bands, covering all fundamental polarization conversion functions. When diodes are ON, it performs as a multifunctional converter at several discrete bands (e.g., 4.9–5.3 GHz, 5.4–15.1 GHz, and 28.5–29.7 GHz), achieving linear-to-linear, linear-to-circular, and circular-to-linear conversions depending on the incident polarization; when diodes are OFF, it acts as a continuous ultra-wideband response unit, maintaining co-polarized reflection for linearly polarized waves and cross-polarized conversion for circularly polarized waves over the 1–28 GHz range. Measured results agree well with simulations. Compared to existing works, our design advances functionality, bandwidth, and incident wave adaptability significantly, providing an efficient solution for advanced wireless systems.