We present a metamaterial for simultaneous optical transparency and microwave absorption in broadband, which can be used as an optically transparent radar-wave absorber. The proposed absorber is made of windmill-shaped elements with the reflection spectra featured by three bands. By properly tailoring resonances structure, we achieve optimized absorptivity that greater than 90% from 8.3 to 17.4 GHz. In meantime, excellent transmittance achieved use indium tin oxide (ITO) film moderate...

Metamaterial absorbers and diffusers provide powerful routes to decrease the backward reflection significantly with advantages of ultrathin profile customized bandwidth. Simultaneous control absorption scattering behaviors metamaterials which helps improve suppression capabilities reflection, however, still remains a challenge. Aiming at this goal, we propose metasurface constituted by two kinds elements in pseudorandom arrangement. By use indium tin oxide moderate sheet resistance...

We propose a low-profile broadband planar circularly polarized folded transmitarray antenna (CPFTA) based on well-designed top and bottom metasurfaces (MSs). The MS is employed to reflect the x-polarized wave as ground and, at same time, convert y-polarized into waves with arbitrary phase shifts in operation band. A applied incident twist its polarization by 90°. whole CPFTA, including feeding source of microstrip antenna, MSs can be fully integrated fabricated using low-cost printed circuit...

We present a conformal metamaterial with simultaneous optical transparency and broadband millimeter-wave absorption for curved surface. By tailoring the reflection response of meta-atoms at oblique angles, it is possible to achieve excellent performance from 26.5 40.0 GHz within wide angular range 0° 60° transverse-electric transverse-magnetic waves. In meantime, by employing transparent substrates, including polyvinyl chloride polyethylene terephthalate, good transmittance (80.1%)...

Abstract We propose a theoretical mechanism and new coding strategy to realize extremely accurate manipulations of nonlinear electromagnetic harmonics in ultrawide frequency band based on time-domain digital metasurface (TDCM). Using the proposed strategy, we design fabricate millimeter-wave (mmWave) TDCM, which is composed reprogrammable meta-atoms embedded with positive-intrinsic-negative diodes. By controlling duty ratios time delays sequences loaded experimental results show that both...

Spatial polarization converter can shift the state of incident wave to another in a specific frequency band. The traditional conversion devices mainly include natural materials and artificial electromagnetic (EM) structures, which are generally sensitive states cannot realize manipulations nonlinear harmonics. These drawbacks limit their developments wireless communications radar detection applications. Herein, general regulation scheme based on anisotropic time‐domain digital coding...

Reconfigurable Intelligent Surface (RIS) has emerged as a promising technology in wireless networks to achieve high spectrum and energy efficiency. RIS typically comprises large number of low-cost nearly passive elements that can smartly interact with the impinging electromagnetic waves for performance enhancement. However, optimally configuring massive remains challenge. In this article, we present machine learning (ML) based modeling approach learns interactions between phase shifts...

In this paper, we survey state-of-the-art research outcomes in the burgeoning field of Reconfigurable Intelligent Surface (RIS), given its potential for significant performance enhancement next-generation wireless communication networks by means adapting a propagation environment. Emphasis has been placed on several aspects gating commercial viability future network deployment. Comprehensive summaries are provided practical hardware design considerations and broad implications artificial...

In the past few years, wireless communications based on digital coding metasurfaces have gained research interest owing to their simplified architectures and low cost. However, in most of metasurface-based systems, a single-polarization scenario is used, limiting channel capacities. To solve problem, multiplexing methods been adopted, but system complexity inevitably increased. Here, space-frequency-polarization-division multiplexed communication proposed using an anisotropic...

We propose a strategy to convert linearly polarized wave from single point source an orbital angular momentum (OAM) by arbitrary polarization via anisotropic frequency selective surface (FSS) in the microwave frequency. By tailoring geometries of FSS elements, reflection-phases x and y polarizations are engineered encoded independently, which allows us design eventual state generated OAM vortex beam elaborately selecting individual coding sequences for each polarization. Two types FSSs...

Abstract Time-domain digital coding metasurfaces have been proposed recently to achieve efficient frequency conversion and harmonic control simultaneously; they show considerable potential for a broad range of electromagnetic applications such as wireless communications. However, achieving flexible continuous wavefront remains an urgent problem. To address this problem, we present Fourier operations on time-domain metasurface propose principle nonlinear scattering-pattern shift using...

Fabricating materials with customized characteristics for both electromagnetic (EM) and acoustic waves remain a significant challenge using the current technology, since demand of multiphysical manipulation requires variety material parameters that are hard to satisfy in nature. However, emergence artificially structured provides new degree freedom tailor wave–matter interactions dual physical domains at subwavelength scale. Here, bifunctional digital coding metamaterial (MM) is proposed...

In this paper, a broadband transparent microwave absorber with fractional bandwidth of 118.1% was designed. the proposed absorber, gear-shaped unit cell consisting optically indium tin oxide-polyethylene terephthalate films fabricated on polymethyl methacrylate is developed to guarantee electromagnetic wave well enter into and dissipated in absorbing structure. Two resonant frequencies at 4.8 GHz 13.6 GHz, which correspond electric resonances, respectively, are generated achieve wide band...

Abstract Metasurfaces are artificially engineered two‐dimensional materials composed of sub‐wavelength meta‐atoms, which have shown unprecedented capabilities in manipulating the amplitude, phase, frequency, and polarization states electromagnetic waves. Specifically, control can be attained via suitable anisotropic, linear, time‐invariant designs, while frequency conversion is realized nonlinear or time‐varying platforms. Simultaneous manipulations would considerable practical interest many...

In the past few years, orbital angular momentum (OAM) has aroused great interest in scientific communities, because it shows potential for enhancing capacities of radio and optical communication systems. Here, we propose anisotropic metasurfaces to generate multiple OAM vortex beams at microwave frequencies. A phase compensation theory is presented, order determine distributions on metasurfaces, This enables independent control beam numbers, polarizations, orientations, topological charges...

Recent advances of space-time-coding digital metasurfaces demonstrate powerful capabilities in the generation nonlinear harmonics and accurate control corresponding wavefronts. However, to date near field manipulation experiment characterization are still not explored. In this paper, we propose a space-time-digital coding metasurface realize fields at fundamental <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mo form="prefix">+</mml:mo>...

Routing acoustic waves without backscattering losses is presently of great interest. Unlike both conventional approaches using defects in sonic crystals and emerging based on topological edge states, this study proposes a radically different theoretical framework that utilizes extremely anisotropic media to engineer backscattering-immune waveguides. The exact condition for one-way wave propagation along zigzag paths derived. proposal experimentally validated spoof surface waves, the results...

Reconfigurable Intelligent Surface (RIS) has emerged as one of the key technologies for 6G in recent years, which comprise a large number low-cost passive elements that can smartly interact with impinging electromagnetic waves performance enhancement. However, optimally configuring massive RIS remains challenge. In this paper, we present novel digital-twin framework RIS-assisted wireless networks name it Environment-Twin (Env-Twin). The goal Env-Twin is to enable automation optimal control...

In this letter, a broadband folded reflectarray (FRA) is designed and fabricated. The FRA consists of main reflectarray, the polarizing grid, feeding dielectric resonator antenna embedded in its structure. With help multilayered reflecting element, capable to provide 90°of polarization rotation proper phase compensation for linearly polarized incident wave. By altering microstrip line length, wide coverage can be obtained with good linearity. To validate design, both simulations experiments...

Abstract Recently, artificially structured metamaterials (MMs) are proposed to manipulate the wave propagation behaviors in single physical domain. However, multiphysics manipulation is rarely reported and remains a challenging issue be investigated. Here, design of MMs with simultaneous controls acoustic electromagnetic (EM) waves presented. A double‐membrane structure meet need acoustic‐wave insulation, patterned anisotropic meta‐atoms on membrane employed generate polarization‐dependent...

&gt;We successfully developed an OLED pixel circuit which has shorter image sticking time and better first frame brightness ratio. The root causes of short‐term (STIS) was also studied. effects TFT EL were tested separately. By matching with the phenomenon STIS, it confirmed that reason STIS is related to characteristic driving thin film transistor (DTFT). DTFT different stress conditions under black/white picture, resulting in difference current gray picture. We could minimize differences...

Concentric spoof surface plasmon hybridization in the microwave frequency is physically realized with subwavelength plasmonic metamaterials. The generated two concentric localized (LSP) particles, where overlap of LSP particles could be tuned to manipulate resonance. Such increase Q factor effectively up 965, and decrease electric dimension particle down 1/7 wavelength. coupled-resonator circuit theory applied analyze interaction mechanism structure strong magnetic coupling. Near...