A dual-band dual-polarisation liquid crystal guided-wave-driven metasurface

Metasurfaces enable versatile electromagnetic wave manipulation through subwavelength meta-atoms, facilitating compact and multifunctional integration. Current metasurface designs mostly depend on external spatial feed structures, increasing complexity and size. This work proposes a low-profile, guided-wave-driven, liquid-crystal (LC)-based programmable metasurface with dual-band, dual-polarisation capabilities for independently controllable, dynamic beam scanning. It consists of an LC-based programmable layer fabricated by standard LCD processes and a broadband waveguide feed structure with high alignment tolerance. A complementary resonance mechanism allows meta-atoms to retain nearly identical radiating-structure dimensions across both frequency bands, overcoming traditional scaling constraints. By dynamically adjusting the LC molecular orientation, the distribution of radiated electromagnetic energy can be precisely controlled. Experimental validation demonstrates exceptional beam scanning capabilities, achieving up to ±75° (150° total) at both frequency bands, surpassing previous designs. In addition, the proposed metasurface achieves controllable near-field focusing by independently programming the aperture amplitude distribution, enabling precise energy localisation at reconfigurable focal positions. The proposed metasurface offers considerable potential for advanced next-generation mobile and satellite communication applications.