Smart metasurface with self-adaptively reprogrammable functions

Abstract

Intelligence at either the material or metamaterial level is a goal that researchers have been pursuing. From passive to active, metasurfaces have been developed to be programmable to dynamically and arbitrarily manipulate electromagnetic (EM) wavefields. However, the programmable metasurfaces require manual control to switch among different functionalities. Here, we put forth a smart metasurface that has self-adaptively reprogrammable functionalities without human participation. The smart metasurface is capable of sensing ambient environments by integrating an additional sensor(s) and can adaptively adjust its EM operational functionality through an unmanned sensing feedback system. As an illustrative example, we experimentally develop a motion-sensitive smart metasurface integrated with a three-axis gyroscope, which can adjust self-adaptively the EM radiation beams via different rotations of the metasurface. We develop an online feedback algorithm as the control software to make the smart metasurface achieve single-beam and multibeam steering and other dynamic reactions adaptively. The proposed metasurface is extendable to other physical sensors to detect the humidity, temperature, illuminating light, and so on. Our strategy will open up a new avenue for future unmanned devices that are consistent with the ambient environment.

Metamaterials: Sensing surfaces that program themselves

A metamaterial surface developed by researchers in China automatically adjusts its electromagnetic properties in response to changes in its environment. Metasurfaces are designed with tiny structures arranged in unique ways to manipulate electromagnetic radiation, and efforts are being made to integrate them with digital coding to produce adaptive, programmable systems. Tie Jun Cui at Southeast University in Nanjing and co-workers have designed smart metasurfaces with integrated sensors that detect features such as movement, light or temperature, linked to a microcontroller which responds by changing the configuration of a metasurface. A potential application of the system would be to help moving airplanes maintain contact with satellites; a gyroscope sensor detects changes in orientation, and the metasurface adapts its electromagnetic properties to ensure that the communication beam will always point in the satellite’s direction.