Liquid-Metal-Tuned Patch Element for Flexible and Reconfigurable Reflectarrays/Intelligent Surfaces

This paper presents a flexible and reconfigurable reflecting element based on liquid metal encapsulated in polydimethylsiloxane (PDMS). The proposed unit cell provides precise reflection phase tuning of over 360° by pneumatically extending or retracting liquid metal in channels spiraling outward from a square patch. The flexible materials are well suited to realize deployable or conformal reflecting surfaces for devices such as reflectarrays or reconfigurable intelligent surfaces (RISs). To demonstrate use of the reflecting element, a curved $12\ \text{element} \times 12\ \text{element}$ array operating at 8.425 GHz is designed and verified using full-wave simulation.