Abstract Metasurfaces are planar structures that can offer unprecedented freedoms to manipulate electromagnetic wavefronts at deep‐subwavelength scale. The wavelength‐dependent behavior of the metasurface could severely reduce design freedom. Besides, realizing high‐efficiency metasurfaces with a simple procedure and easy fabrication is great interest. Here, novel approach highly efficient meta‐atoms achieve full 2π phase coverage two wavelengths independently in transmission mode proposed....

Abstract Physical layer metasurface‐empowered cryptography offers a novel approach to secure encryption. This study proposes an encryption method with robustness, high capacity, and enhanced security based on the dual‐band complex‐amplitude metasurface. By leveraging American Standard Code for Information Interchange (ASCII), both secret message compressed digital signature are encrypted transmitted together, eliminating codebook transmission reducing risks. The modified Visual Secret...

Vortex beams (VBs) carrying orbital angular moment (OAM) modes have been proven to be promising resources for increasing communication capacity. Although considerable attention has paid on metasurface-based VB generators due the unprecedented advantages of metasurface, most applications are usually limited at a single band with fixed OAM mode. In this work, an emerging dual-band reflection-type coding metasurface is proposed mitigate these issues by newly engineered meta-atoms, which could...

Abstract Meta‐devices have attracted great interest due to the unprecedented capabilities of manipulating wavefronts. Complex‐amplitude hologram can provide high‐quality images that be free ghost and undesired diffraction orders. However, conventional meta‐holograms usually operate at a single band with phase‐only modulation. Here, reflective 2‐bit meta‐hologram is proposed independent complex‐amplitude modulations two frequency bands. The high‐efficiency meta‐atom composed top perforated...

Objective: To investigate the biomechanical properties of lens and changes before after cycloplegia in myopic population China, to analyze possible influencing factors. Methods: This is a cross-sectional study. Consecutively, 159 patients (159 right eyes) who underwent Brillouin Optical Scanning System examination from November 2023 May 2024 at Tianjin Eye Hospital were recruited. Among them, 82 male 77 female, with an age 21 (18, 24) years. The classified into low, intermediate, high myopia...

The wavelength-dependent behavior of the metasurface is one severe disadvantages in metasurface-based applications, which greatly limits its applications. In this work, a novel reflective building block (unit cell) has been proposed to work at two arbitrary terahertz frequency bands with independent phase control each band. geometric can reflect incident circularly polarized wave and convert it opposite helicity high conversion efficiencies both bands. As proof concept demonstrations,...

Abstract Full‐space metasurfaces have attracted significant interest due to their unprecedented abilities tailor the electromagnetic wavefronts in both transmission and reflection half‐spaces. However, it remains difficult challenging achieve high‐efficiency complex‐amplitude modulation within a single‐substrate‐layer structure for circularly polarized (CP) waves, which can enhance power distribution regulation. Herein, universal design strategy frequency‐multiplexed full‐space meta‐device...

Abstract The Airy beam has attracted considerable interests due to its remarkable non‐diffracting, self‐bending, and self‐healing properties. An auto‐focusing (AFA) can be achieved by constructing two counter‐propagation beams, which is a novel method generate focusing effect. Traditionally, because of the complexity generation mechanism, it hard realize with complex amplitude modulation. reported ones usually require bulky optical systems typically work at one single wavelength. Here,...

In this communication, a novel nonresonant metamaterial (MTM) structure is proposed to enhance the gain of clamped-mode planar log-periodic dipole array (CMPLPDA) antenna fed by substrate integrated waveguide. The MTM structures composed series metallic semiring patches are printed on both sides substrate, featuring low loss, broadband, and easy integration. Different arrangements with respect dipoles CMPLPDA investigated compared. gain-enhanced method based has been studied through...

Holography is an advanced imaging technology where image information can be reconstructed without a lens. Recently, multiplexing techniques have been widely adapted to realize multiple holographic images or functionalities in meta-hologram. In this work, reflective four-channel meta-hologram proposed further increase the channel capacity by simultaneously implementing frequency and polarization multiplexing. Compared single technique, number of channels achieves multiplicative growth two...

Abstract Metasurface has drawn much attention due to its unprecedented wave‐front manipulation abilities with an ultrathin flat profile. However, the metasurface as a diffractive device usually suffers from chromatic aberrations, which greatly hinders design freedom at different wavelengths. In this work, it is demonstrated that limitation can be overcome by multifunctional completely independent phase modulations three arbitrarily Specifically, novel single‐layer tri‐spectral meta‐atom...

In this paper, the synthesis problem of plane wave applied to 5G communication measurement is studied by means theoretical analysis and computer simulation. A generator (PWG) working at 28 GHz designed realize near-field antenna measurement. The PWG consists 21 × units, whose amplitude phase are figured out using least squares method (LSM). numerical simulation results indicate that high-purity synthesized in quiet zone with 20λ 7λ. frequency bandwidth 12 covering system band 5G. max error...

Heterostructures play a pivotal role in the design of valley-locked waveguides, facilitating manipulation width as an additional degree freedom. Through this design, we demonstrate extension topological guided modes from domain wall topologically nontrivial valley photonic crystals (VPCs) into trivial VPCs. We propose C

Abstract The significance of a cryptograph method lies in its ability to provide high fidelity, security, and large capacity. emergence metasurface-empowered cryptography offers promising alternative due unparalleled wavefront modulation capabilities easy integration with traditional schemes. However, the majority reported strategies suffer from limited capacity as result restricted independent information channels. In this study, we present novel that utilizes dual-band complex-amplitude...

An H-shape dielectric resonator antenna with U-slot on the patch is presented in this paper, mounted vertical ground plane edge. The etched to obtain isolation from WLAN frequency (5.125 GHz– 5.825 GHz). bands for S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> ≤ −10 dB are 3.61 GHz 4.80 and 6.05 9.56 GHz, respectively. bandwidths gain can satisfy detection requirement, kind of be used detect breast tumor due its permittivity 10.2...

Metasurfaces are engineered planar surfaces consisting of arrays resonators for tailoring the electromagnetic wavefronts in a desirable way. However, spin-locked issue geometric metasurfaces hinders simultaneous manipulation both spins. In this work, spin-decoupled information metasurface composed simple C-shaped is proposed to realize two different channels under orthogonal circularly polarized (CP) incidences. Based on encoded digit '0' or '1', diffusion scattering holographic image could...

In this paper, the application of dielectric resonator antenna (DRA) array in 5G communication system is studied. Firstly, an 8-way Wilkinson power divider with fold structure designed, whose port phase and transmission efficiency are applicable for a feed network. Secondly, kind semi cylindrical DRA unit operated on 28 GHz presented. It fed by aperture coupled microstrip line. The 8-unit uniform linear made up unit. simulation result given which shows that both bandwidth gain can better...

Vortex beams carrying orbital angular momentum (OAM) are of great importance owing to the capacity expand channel communication systems from microwave optical regimes. In this work, a single-layer ultra-broadband meta-atom is designed by using method fractal. The reflected co-polarization amplitude arrow-based fractal can exceed 0.9 in frequency range 6 19.7 GHz and complete 2π phase control be achieved rotating structure. Based on proposed meta-atom, metasurface-based vortex beam generators...

Achieving multitasking wavefront manipulations at multiple frequencies within a planar meta‐device is pivotal for increasing data density and functionality diversity yet still challenging in integrated devices. Considering both high efficiency compactness, herein, high‐efficiency reflective metasurface based on single‐cell meta‐atoms with independent complex‐amplitude modulations three distinct under the circularly polarized incidence demonstrated, which can facilitate formation of mutually...

Abstract Multichannel devices, which can manipulate multiple distinguished wavefronts like a kaleidoscope, are preferably desired for compact systems with higher integration and smaller footprint. Particularly, multiband metasurfaces one of the intuitive effective approaches to expand number operation channels in meta‐devices. In this work, strategy design four‐channel metasurface based on novel single‐cell quad‐band meta‐atom is proposed kaleidoscopic wavefront manipulations. While...

In this paper, a novel microstrip antenna using interdigital capacitor is proposed. The DGS technology used to further reduce the size of antenna. improved 24% traditional rectangular antenna, and has frequency range 2.4-2.52 GHz with maximum gain 2.35 dB, meet requirement for ISM band applications, realize miniaturization design.

Abstract In this work, an ultra‐wideband double slot Vivaldi antenna (DSVA) loaded with a novel wideband nonresonant metasurface is proposed to enhance the gain. The semi‐elliptical slots are etched on both sides of ground plane DSVA improve current distribution. addition, composed WiFi‐shaped unit cells could maintain stable high refractive index in operating bandwidth 1−18 GHz, which bend outgoing wave end‐fire direction. Both original and simulated, fabricated, characterized. measured...

Metasurfaces with complex-amplitude modulation are superior in power regulation and hologram imaging resolution compared those phase-only modulation. Nevertheless, a single-cell metasurface multi-band independent phase amplitude controls is still great challenge for the circularly polarized incidences. In this work, we propose design single-substrate-layer modulations at two discrete frequencies. Based on emerging technique, bi-spectral meta-hologram designed verified by both full-wave...

Achieving wavelength-independent behavior in a single metasurface is of great significance for electromagnetic integrated system. In this work, novel dual-band meta-atom proposed reflecting the incident wave to its cross-polarized component with high efficiencies. Beside phase modulation, amplitude can also be tailored independently at two gigahertz frequencies. As demonstration example, bifocal reflective metalens designed and numerically verified. The full-wave simulation results are good...