Metasurface Salisbury screen: achieving ultra-wideband microwave absorption

Abstract

The metasurfaces have recently been demonstrated to provide full control of the phase responses of electromagnetic (EM) wave scattering over subwavelength scales, enabling a wide range of practical applications. Here, we propose a comprehensive scheme for the efficient and flexible design of metasurface Salisbury screen (MSS) capable of absorbing the impinging EM wave in an ultra-wide frequency band. We show that properly designed reflective metasurface can be used to substitute the metallic ground of conventional Salisbury screen for generating diverse resonances in a desirable way, thus providing large controllability over the absorption bandwidth. Based on this concept, we establish an equivalent circuit model to qualitatively analysis the resonances in MSS and design algorithms to optimize the overall performance of the MSS. Experiments have been carried out to demonstrate that the absorption bandwidth from 6 GHz to 30 GHz with an efficiency higher than 85% can be achieved by the proposal, which is apparently much larger than that of conventional Salisbury screen (7 GHz - 17 GHz). The proposed concept of MSS could offer opportunities for flexibly designing thin electromagnetic absorbers with simultaneously ultra-wide bandwidth, polarization insensitivity, and wide incident angle, exhibiting promising potentials for many applications such as in EM compatibility, stealth technique, etc.

Magnetic–acoustic biphysical invisible coats for underwater objects

“…However, considering the practical scenario where the probing distance is usually kilometers away, the side scattering for a singlestation detection system may not be as serious, as the absorber is mostly explored for normal incidence. On the other hand, there will be techniques to broaden the angular response just like their EM counterparts [44][45][46] .…”

Broadband microwave metamaterial absorber with lumped resistor loading

“…One of the most well-known structures is the Salisbury screen absorber [13], with a thin homogeneous resistive sheet suspended above a ground plane by a distance of a quarter of a wavelength. By replacing the ground plane with judiciously designed metasurface, the bandwidth of the Salisbury screen can further be significantly improved due to the excitation of multiple metasurface Salisbury screen resonances [14,15]. Besides, loading with other types of lossy components such as magnetic medium [16,17], resistive sheets [18,19], lumped elements [20][21][22][23], and lossy liquid water [24,25] can be good candidates for potentially broadening the absorption bandwidth, but most of them are limited by the angular stability, which may further hinder their practical uses.…”

Hybrid graphene metasurface for near-infrared absorbers

“…With the flexibility of current state-of-the-art nanofabrication approaches, recent developments of metasurfaces [8] can yield near perfect light absorption in the visible [9], near-infrared [10], mid-infrared [11], and far-infrared [12] regions. Among these perfect absorbers, the three-layer configuration is designed with a metasurface on the top, a dielectric spacer in the middle, and a metallic reflector at the bottom, which is analogous to so-called Salisbury screen [13]. However, these metasurface-based absorbers are usually fabricated using sophisticated lithography techniques, such as E-beam lithography [14], laser interference lithography [15], self-assembly [16], and nanoimprint lithography [17], which limits large-scale mass production.…”