Liquid-Metal-Based Reconfigurable Intelligent Surfaces

A typical reconfigurable intelligent surface (RIS) consists of an array of unit cells, each containing a few unconnected conducting segments. Reconfiguration of the array, and thus its reflective properties, is usually achieved using varactor or PIN diodes serving as switches to connect/disconnect the otherwise isolated conducting segments. This results in a different geometry for each unit cell, which can then be patterned in a way to create a phase gradient across the array surface, resulting in redirection of an incident electromagnetic wave in a specified direction.