Reconfigurable Metasurfaces for Frequency Selective Absorption

Abstract

Metasurfaces can provide novel functionality for absorbing electromagnetic waves through a periodic array of inductive/capacitive resonators by controlling the material's permittivity and permeability. This attractive characteristic makes them widely applicable to various electromagnetic applications. However, conventional metasurfaces are dispersive and suffer from a narrow bandwidth with uncontrollable and unchangeable functions because the effective permittivity and permeability are tailored to a certain resonance frequency. Therefore, many studies have focused on how to increase the absorption frequency bandwidth and control the absorption frequency by using reconfigurable metasurfaces. This paper presents a report on the most recent progress in the realization of reconfigurable metasurfaces based on advanced materials for frequency‐selective absorption in the microwave, millimeter‐wave, sub‐terahertz, terahertz, and visible ranges. Furthermore, their tuning ratios for different advanced materials and spectra are summarized and compared. This progress report provides guidelines for the material selection for and the design of reconfigurable metasurfaces.

A Microvascular‐Based Multifunctional and Reconfigurable Metamaterial

“…Reconfigurable electronics have emerged to provide bandwidth versatility in an increasingly occupied and monitored radio frequency (RF) spectrum. While various approaches rely on surface-mounted devices or structural changes (e.g., origami) to modulate electromagnetic signature, [86,87] structurallyembedded electronics offer enhanced physical protection and reduce overall material footprint. Liquid metal microfluidics is an emerging embedded modality for implementing electromagnetic (EM) reconfiguration in a variety of material systems.…”

“…[15,17,43,[88][89][90] This internal strategy provides EM flexibility without external geometrical modifications, especially important for aerodynamic structures, and eliminates additional bias circuitry. [86] While several prior studies in structural composites demonstrate promise for local topology changes using liquid metal, [15,17,19] the ability of pervasive liquid metal patterning to achieve reconfiguration of equivalent bulk material properties-a main focus of this section-has been studied to a much lesser extent.…”

A High‐Performance Nonlinear Metasurface for Spatial‐Wave Absorption

“…[ 49 ] Based on this principle, a myriad of absorbers based on pyramids or wedges loaded with lossy material, [ 48 ] ferrite–graphene composites, [ 49 ] carbon fiber, [ 50 ] metamaterial, [ 48 ] graphene, [ 51,52 ] to name a few, are delicately designed by optimizing the impedance‐match feature. Resonance‐based absorbers, such as the classic Salisbury screen, [ 53 ] Jaumann absorber, [ 54 ] circuit analog absorber, [ 55 ] and those newly proposed metasurface absorbers, [ 56 ] can also be explained by this theory. However, almost all these investigations did not consider the nonlinearities of input impedances, which means that the absorption rates kept stable if microwave intensities changed.…”

Design and Synthesis Strategies: 2D Materials for Electromagnetic Shielding/Absorbing

“…To satisfy the requirement of low thickness, lightweight, strong attenuation and wide bandwidth, researches are focused on carbon materials, [16,17] transition metal compounds, [18] conductive polymers [19] and metamaterials [20] . Among of them, two‐dimensional(2D) materials display unique advantages for EMI shielding and absorbing because of the layer structure, energy band structure, electronic characteristics and controlled plane structure [21,22] .…”