Wavenumber‐Splitting Metasurfaces Achieve Multichannel Diffusive Invisibility

Abstract

The emerging invisibility schemes mainly adopt transformation optics, scattering cancellation, light diffusion, and metasurface‐based phase restoration techniques. However, those aforementioned invisibility achievements natively depend on the predefined curvature, polarization, frequency, and/or angle of the incident wave. Here, an invisibility strategy of using an ultrathin parabolic‐phase metasurface and its applications to achieve diffusive invisibility for dual‐polarization channels and multifrequency channels is reported. Such strategy can intrinsically split the wavenumber of the scattering wave and therein is termed as wavenumber‐splitting metasurface. For verification, two proof‐of‐concept examples are experimentally characterized. The first prototype manifests dual‐polarized near‐isotropic diffusive scattering immune from wide‐angle incidences. The second demonstration exhibits bifunctionality of combined diffusive invisibility and vortex scattering in dual‐polarization channels. In both cases, theoretical, numerical and experimental results agree well, illustrating a well‐separated triple‐band versatile scattering behavior. This approach addresses the fundamental issue of real invisibility under bistatic detection without complex optimization, thanks to the physical essence of numerous splitting wave vectors. Such strategy opens an upstream way to realize invisibility as well as holding the potentials for downstream applications such as stealth and camouflaging devices.

Radar cross section reduction metasurfaces based on phase gradient and chessboard structure

“…It is seen that the proposed structure has a wider bandwidth (RCS reduction >10 dB) compared with the Refs. 4, 7, and 16. Although Refs.…”

“…Metasurface (MS) is a kind of artificial materials that can be used to control the reflection/transmission EM waves with different resonant frequency, phase, and polarization. Many different kinds of MSs have been proposed to reduce RCS, such as the perfect MS absorbers, 1,2 the artificial magnetic conductor chessboard structure, [3][4][5] phase random metasurface [6][7][8][9][10][11] (PRM), and phase gradient metasurface (PGM). [12][13][14][15][16][17] In 2017, a wideband RCS reduction based on the chessboard polarization conversion MS was proposed whose phase differences were preserved as 180 AE 37 .…”

High gain transmitarray antenna based on ultra‐thin metasurface

“…In recent years, metasurface (MS) are getting more and more attention and finding its application in many fields because of its flexibility and manufacturing convenience . Compared with bulk metamaterial, the MS shows significant advantages in both microwave and optical frequencies, such as less loss, smaller dimensions, easier to assemblage, and so on.…”

“…In recent years, metasurface (MS) are getting more and more attention and finding its application in many fields because of its flexibility and manufacturing convenience. [1][2][3][4] Compared with bulk metamaterial, the MS shows significant advantages in both microwave and optical frequencies, such as less loss, smaller dimensions, easier to assemblage, and so on. With the elicitation by Pendry's super lens and demonstration of the generalized Snell's law by Yu et al 5,6 the theory of MS develops rapidly in the field of beam steering and lens focus.…”

Dual-functional active frequency selective surface using parallel feeding configuration and its equivalent circuit model

“…The functional diversity and the state variability of many newly developed electronic devices necessitate the design of multifunctional structures that possess multiple functional states . In reference , a dual‐functional metasurface is presented to flexibly control the emission beams. Circularly‐polarized bifunctional metasurfaces, which can control electromagnetic waves depending on handedness, are realized .…”