One-dimensional photonic crystals (1DPCs) based on ZnS/Ge for compatible stealth of infrared and visible were firstly proposed theoretically and investigated experimentally. Owing to the equal ...inclination interference, the designed 1DPCs structure can be fabricated with a certain color corresponding to the different responded wavelength. In addition, the average emissivity of the proposed structure can reach as low as 0.054 at infrared atmosphere window of 3–5 μm. The as-prepared structure indicates that it is feasible for 1DPC to achieve infrared-visible compatible stealth.
•ZnS/Ge one-dimensional photonic crystal structure was firstly reported to achieve infrared-visible compatible stealth.•Ultra-low infrared average emissivity 0.054 was obtained at infrared atmosphere window of 3–5 μm.•Thin films with certain colors were fabricated due to the equal inclination interference.
•A plasmonic perfect absorber (PA) was proposed to serve as a refractive index sensor.•The PA with a high quality-factor of 41.2 and an absorbance of 99.9% at 142.6THz.•Physics origin of PA is ...studied by field, current distribution and LC circuit model.•The PA for refractive index sensor yields a sensitivity of 1445nm/RIU.
We present a non-planar all-metal plasmonic perfect absorber (PA) with response polarization independent in infrared region, which can be served as a sensor for enhanced refractive index sensing. Distinct from previous designs, the proposed PA consisted of all metal structured film constructed with an assembly of four-tined rod resonators (FRRs). The PA with a high quality-factor (Q-factor) of 41.2 and an absorbance of 99.9% at 142.6THz has been demonstrated numerically. The resonance behavior occurs in the space between the rods of the FRRs, which is remarkable different conventional sandwiched structural PAs. Based on equivalent LC circuit theory, the absorption peak can be finely tuned by varying the geometrical dimensions of the FRRs. Furthermore, the resonance frequency shows highly sensitive response to the change of refractive index in the surrounding medium. A careful design for refractive index sensor can yield a sensitivity of 1445nm/refractive index unit (RIU) and a figure of merit (FOM) of 28.8. The demonstrated design of the plasmonic PA for sensing provides great potential application in enhancing refractive index sensors and the enhanced infrared spectroscopy.
In this paper, an ultrathin transparent metamaterial polarization transformer using a circular twist-split-ring resonator (TSRR) was proposed and investigated experimentally and numerically. The ...experimental and simulated results exhibit an asymmetric transmission only for forward and backward propagating linearly polarized waves. An incident linearly polarized wave can convert its polarization nearly completely to the cross direction after transmission under certain conditions. The simulated spatial evolution of the electric field further indicates that the twist structure functions as a perfect polarization transformer at certain frequencies.
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•This multifunctional metastructure achieves independent manipulation of structural dual-functions.•Absorption band broadens due to reactance compensation effect and multiple ...resonance modes derived by the multi-layer high impedance surface.•Compression and flexure resistance can be improved by adjusting specific structural parameters of honeycomb.
Recently, lightweight multifunctional metastructures have attracted significant attention owing to its advantage of integrating microwave absorption and mechanical resistance. However, these features are typically entangled, and a feasible strategy for independently manipulating the microwave absorption and mechanical resistance is still lacking. Herein, a double high-impedance surface-loaded honeycomb (DHHC) is proposed, based on a theoretical analysis, and fabricated using a 3D printing technique. The impedance and surface current distribution of the DHHC were analyzed and investigated to achieve broadband microwave absorption characteristics. The structural parameters and resistances of the high-impedance surface were investigated and optimized to regulate the absorbing bandwidth and reflectivity intensity. Our experimental results indicated that a 4.25 mm thick DHHC metastructure can achieve a –10 dB absorbing bandwidth at a frequency range of 6.73–18 GHz, as well as a –15 dB absorbing band at 8.42–14.75 GHz. Moreover, the structural parameters of the honeycombs were investigated for the adjustment of stress distributions during the compression and flexural processes. Load-bearing tests indicated that the DHHC possessed a mechanical resistance with an equivalent areal density of 2.32 kg/m2. This study provides a promising route for achieving independently manipulated compatibility between microwave absorption and mechanical resistance for practical applications.
Titanium boride (TiB
2
) particles and fibers were synthesized by the carbothermal method with different calcination temperatures and time. Subsequently, the effects of calcination temperatures and ...time on microstructure and the yield of TiB
2
fibers were investigated. Further, the dielectric and microwave absorption (MA) properties of TiB
2
/paraffin composites within 2–18 GHz were discussed. As a result, the yield of TiB
2
fibers reached a maximum at 1400 °C for 180 min. The content of TiB
2
was directly proportional to permittivity. The sample containing 80 wt % TiB
2
particles and fibers indicated that the minimum reflection loss (
RL
min
) attained − 46.5 dB at 11.6 GHz when the thickness was 1.45 mm and the effective absorption bandwidth (EAB) was 4.64 GHz (
RL
<–10 dB) with the thickness of 1.25 mm. The related MA mechanisms were also discussed. The excellent stability, simple production procedure, thin absorbing layer, and wide EAB make TiB
2
become an ideal candidate for microwave absorbing materials applied in high temperatures.
Honeycomb structure coated with paraffin filled with composite of graphene and flaky carbonyl iron powder (FCIP) as lossy filler have been studied. The composite of graphene/FCIP with different ...weight ratio were synthesized via mechanical milling, the electromagnetic properties of the samples were measured by transmission/reflection method in the frequency range of 8-12 GHz. The microwave absorbing properties of the microwave absorbing honeycomb structure (MAHS) and microwave absorbing honeycomb sandwich structure (MAHSS) were studied based on the Finite Element Method with periodical boundary conditions. The matching layer on the top of the honeycomb sandwich structure can enhanced the microwave absorption properties. It was shown that a light weight and broadband MAHSS could be implemented with the use of the magnetic material and dielectric material.
A brand-new approach to realizing visible-infrared compatible camouflage is proposed based on a metal-based graphical hetero-structure (MGHS) SiO₂/Ag/ZnS/Ag. For different thicknesses (20, 40, and 60 ...nm) of color-controlling sub-layer, high-contract and large-span structure colors (yellow, navy, and cyan) were observed due to reintroducing constructive interference with a matching intensity of reflected waves. Ultra-low infrared emissivity values of 0.04, 0.05, and 0.04 (with high average reflectance values of 95.46%, 95.31%, and 95.09%) were obtained at 3⁻14 μm. In addition, the well-performing trisecting-circle structure further indicates that it is feasible to design on-demand compatible camouflage patterns using the easily-prepared MGHS.
In this study, a polarization-independent phase-gradient metasurface (PGM) for spoof surface-plasmon-polariton (SPP) coupling is proposed and investigated using theoretical simulations and ...experiments. The designed PGM is composed of a periodic array, which consists of a dielectric spacer sandwiched between a metallic petal structure and metal film. The numerical results indicate that, when the composite surface wave vector is greater than that of the incident wave, an arbitrarily incident linearly polarized electromagnetic wave can be efficiently coupled to yield a spoof SPP. The results obtained from both simulation and experiments are consistent with theoretical predictions. The PGM spoof SPP coupler design is polarization independent and highly efficient at the X-band.
The structural and electromagnetic properties of gas atomized Fe–Cr–Si–Al alloy (SMSS) powders flattened by ball milling were studied. It is found that the aspect ratio of the powders with the same ...particle sizes of 48–55
μm increases with the milling time. With the increase of the aspect ratio, the complex permittivity, permeability and intensity of reflectivity peak increase, respectively, and the matching frequency shifts to low frequency due to the improved wave impedance matching and the increase of real part of complex permittivity and permeability. A similar trend of the microwave properties with the decrease of the particle size can be also observed.
Co0.5Ni0.5Fe2O4 fibers with a diameter of about 270 nm and a length of about 10 μm were synthesized by a microemulsion-mediated solvothermal method with subsequent heat treatment. The Co0.5Ni0.5Fe2O4 ...fibers/reduced graphene oxide (RGO) composite was prepared by a facile in-situ chemical reduction method. The crystalline structures and morphologies were investigated based on X-ray diffraction patterns and scanning electron microscopy. Magnetization measurements were carried out using a vibrating sample magnetometer at room temperature. Co0.5Ni0.5Fe2O4 fibers/RGO composites achieve both a wider and stronger absorption and an adjustable surface wave attenuation compared with Co0.5Ni0.5Fe2O4 fibers, indicating the potential for application as advanced microwave absorbers.
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