Programmable microfluidic metasurfaces for reconfigurable beam steering

This Letter introduces the concept of programmable microfluidic metasurfaces for reconfigurable beam steering, addressing the limitations of conventional metasurfaces that rely on nonlinear materials, PIN diodes, and varactors. By integrating liquid-based reconfigurable metasurfaces with programmable metasurfaces, our approach leverages liquid metals such as EGaIn (eutectic gallium–indium) to achieve real-time, reconfigurable beam steering with enhanced adaptability. This method offers key advantages, including cost-effectiveness, ease of shaping, and tunability. Notably, the proposed system maintains consistent performance across two distinct frequency regions, enabling simultaneous dual-band operation. In addition, the programmed beam-form, under normal incidence conditions, rotates in close accordance with the conventional law of reflection when subjected to oblique incidence, for angles up to around 40°. This key result not only validates the metasurface's capability to direct signals to specific areas or users but also unlocks possibilities for real-time beam control. Crucially, the proposed device can be fabricated using a combination of standard printed circuit board manufacturing techniques and conventional microfluidic channel fabrication methods, ensuring scalability and practicality for large-scale deployment.