Anisotropic metamaterial with the ε-near-μ property in the entire angular domain enables broadband all-angle transmissions

Abstract Epsilon-near-mu metamaterials play a significant role in many fields such as radar, communication, and stealth technology, due to their ideal transmission responses. However, when electromagnetic (EM) waves illuminate such metamaterials at large angles, undesired reflectance occurs that greatly restricts the applications. Here, we propose a theoretical approach that can fundamentally eliminate the adverse effects of the incident angle on the transmission response of an anisotropic ε-near-μ material by adjusting the structural permittivity and permeability tensors. We take advantages of the nonresonance regions of electric and magnetic resonators so that the material parameters can attain the desired values in a wide frequency band. This allows us to design a nonreflective material with broadband all-angle transmissions from 0° to almost 90°, which is further verified by experiments with good performance. This work opens up a new route for the design of ultrawide-angle transmission-type metamaterials with high-efficiency and wideband properties, reaching significant applications in antenna radomes.

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On-chip trans-dimensional plasmonic router

Nanophotonics ◽

10.1515/nanoph-2020-0078 ◽

2020 ◽

Vol 9 (10) ◽

pp. 3357-3365 ◽

Cited By ~ 1

Author(s):

Shaohua Dong ◽

Qing Zhang ◽

Guangtao Cao ◽

Jincheng Ni ◽

Ting Shi ◽

...

Keyword(s):

High Speed ◽

High Efficiency ◽

Incident Angle ◽

Reciprocal Lattice ◽

Plasmonic Waveguide ◽

Optical Diffraction ◽

Local Dynamic ◽

Phase Gradient ◽

On Chip ◽

Plasmon Polaritons

AbstractPlasmons, as emerging optical diffraction-unlimited information carriers, promise the high-capacity, high-speed, and integrated photonic chips. The on-chip precise manipulations of plasmon in an arbitrary platform, whether two-dimensional (2D) or one-dimensional (1D), appears demanding but non-trivial. Here, we proposed a meta-wall, consisting of specifically designed meta-atoms, that allows the high-efficiency transformation of propagating plasmon polaritons from 2D platforms to 1D plasmonic waveguides, forming the trans-dimensional plasmonic routers. The mechanism to compensate the momentum transformation in the router can be traced via a local dynamic phase gradient of the meta-atom and reciprocal lattice vector. To demonstrate such a scheme, a directional router based on phase-gradient meta-wall is designed to couple 2D SPP to a 1D plasmonic waveguide, while a unidirectional router based on grating metawall is designed to route 2D SPP to the arbitrarily desired direction along the 1D plasmonic waveguide by changing the incident angle of 2D SPP. The on-chip routers of trans-dimensional SPP demonstrated here provide a flexible tool to manipulate propagation of surface plasmon polaritons (SPPs) and may pave the way for designing integrated plasmonic network and devices.

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Broadband, High‐Efficiency and Wide‐Incident‐Angle Anomalous Reflection in Groove Metagratings

Annalen der Physik ◽

10.1002/andp.202100149 ◽

2021 ◽

pp. 2100149

Author(s):

Chuanbao Liu ◽

Jingjin He ◽

Ji Zhou ◽

Jianchun Xu ◽

Ke Bi ◽

...

Keyword(s):

High Efficiency ◽

Incident Angle ◽

Anomalous Reflection

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Reflective and transmissive cross-polarization converter for terahertz wave in a switchable metamaterial

Physica Scripta ◽

10.1088/1402-4896/ac46f5 ◽

2021 ◽

Author(s):

Yuanyuan Jiang ◽

Man Zhang ◽

Weihua Wang ◽

Zhengyong Song

Keyword(s):

Vanadium Dioxide ◽

High Efficiency ◽

Incident Angle ◽

Terahertz Wave ◽

Polarization Conversion ◽

Cross Polarization ◽

Polarization Converter ◽

Metallic Grating ◽

Vanadium Dioxide Film ◽

Wave Conversion

Abstract Utilizing the phase transition characteristic of vanadium dioxide, we present a metamaterial configuration to achieve both reflective and transmissive cross-polarization converters. When vanadium dioxide is metal, the design behaves as a reflective cross-polarization converter. It consists of metallic grating, topas spacer, and vanadium dioxide film. Polarization conversion ratio is more than 90% in the frequency range from 4.80 THz to 13.13 THz. When vanadium dioxide is insulator, the design behaves as a transmissive cross-polarization converter using cascaded metallic gratings with rotation angle . High-efficiency broadband cross-polarization wave conversion is achieved in the frequency band of 0.50-4.75 THz. The effects of oblique incidence on reflective and transmissive modes are studied on polarization conversion. The results tell that cross-polarization conversion is better when incident angle is in the range of -. The designed metamaterial may have a certain inspiration for the research of terahertz multifunctional polarization converter.

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Adjustable sound insulation frequency band through the combination of membrane-type acoustic metamaterial array

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-3472 ◽

2021 ◽

Vol 263 (1) ◽

pp. 5869-5877

Author(s):

Xiang Wu ◽

TengLong Jiang ◽

JianWang Shao ◽

GuoMing Deng ◽

Chang Jin

Keyword(s):

Thin Films ◽

Frequency Band ◽

Transmission Loss ◽

Structural Parameters ◽

Sound Insulation ◽

Acoustic Metamaterials ◽

Additional Mass ◽

Acoustic Metamaterial ◽

Material Parameters ◽

Membrane Type

Membrane-type acoustic metamaterials are thin films or plates composed of periodic units with small additional mass. A large number of studies have shown that these metamaterials exhibit tunable anti-resonance, and their transmission loss values are much higher than the corresponding quality laws. At present, most researches on membrane-type acoustic metamaterials focus on the unit cell, and the sound insulation frequency band can only be adjusted by adjusting the structural parameters and material parameters. In this paper, two kinds of acoustic metamaterials with different structures are designed, which are the center placement of the mass and the eccentric placement of the mass.The two structures have different sound insulation characteristics. By designing different array combinations of acoustic metamaterials, the sound insulation peaks of different frequency bands are obtained. This paper studies the corresponding combination law, and effectively realizes the adjustable sound insulation frequency band.

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Fault Diagnosis of Rolling Bearings Based on Improved Kurtogram in Varying Speed Conditions

Applied Sciences ◽

10.3390/app9061157 ◽

2019 ◽

Vol 9 (6) ◽

pp. 1157 ◽

Cited By ~ 4

Author(s):

Yong Ren ◽

Wei Li ◽

Bo Zhang ◽

Zhencai Zhu ◽

Fang Jiang

Keyword(s):

Frequency Band ◽

Band Pass Filter ◽

Angular Domain ◽

Optimal Frequency ◽

Rolling Bearings ◽

Pass Filter ◽

Bearing Fault ◽

Order Spectrum ◽

Resonance Band ◽

Speed Fluctuation

Envelope analysis is a widely used method in fault diagnoses of rolling bearings. An optimal narrowband chosen for the envelope demodulation is critical to obtain high detection accuracy. To select the narrowband, the fast kurtogram (FK), which computes the kurtosis of a set of filtered signals, is introduced to detect cyclic transients in a signal, and the zone with the maximum kurtosis is the optimal frequency band. However, the kurtosis value is affected by rotating frequencies and is sensitive to large random impulses which normally occur in industrial applications. These factors weaken the performance of the FK for extracting weak fault features. To overcome these limitations, a novel feature named Order Spectrum Correlated Kurtosis (OSCK) is proposed, replacing the kurtosis index in the FK, to construct an improved kurtogram called Fast Order Spectrum Correlated Kurtogram (FOSCK). A band-pass filter is used to extract the optimal frequency band signal corresponding to the maximum OSCK. The envelope of the filtered signal is calculated using the Hilbert transform, and a low-pass filter is employed to eliminate the trend terms of the envelope. Then, the non-stationary filtered envelope is converted in the time domain into the stationary envelope in the angular domain via Computed Order Tracking (COT) to remove the effects of the speed fluctuation. The order structure of the angular domain envelope signal can then be used to determine the type of fault by identifying its characteristic order. This method offers several merits, such as fine order spectrum resolution and robustness to both random shock and heavy noise. Additionally, it can accurately locate the bearing fault resonance band within a relatively large speed fluctuation. The effectiveness of the proposed method is verified by a number of simulations and experimental bearing fault signals. The results are compared with several existing methods; the proposed method outperforms others in accurate bearing fault feature extraction under varying speed conditions.

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Optical Analyses of Microfluidic Tunable Liquid Prisms for Enhanced Solar Energy Collection

Volume 6B: Energy ◽

10.1115/imece2014-37797 ◽

2014 ◽

Author(s):

Abhishek Wadhwa ◽

Sung-Yong Park

Keyword(s):

Refractive Index ◽

Solar Energy ◽

Reflection Loss ◽

High Efficiency ◽

Material Selection ◽

Incident Angle ◽

Tracking System ◽

Low Cost ◽

Beam Steering ◽

Index Ratio

We present optical analyses of a microfluidic tunable liquid prism to find its optimized configuration that can achieve wider beam steering as well as less reflection loss and eventually maximize solar energy capture without mechanical tracking. For this study, four different prism configurations are compared from single to quad-stacked ones with various refractive indices of the liquids filled in the prism. Its beam steering capability can be improved by increasing the refractive index ratio between the liquids used and by using higher number of the stacked prisms. The quad-stacked prism is able to steer incoming sunlight with an incident angle of a α ≤ ± 75° at an apex angle of φ ≤ ± 30°, which represents more than 5 times improvement, when it is compared to the single prism using the same liquids. For appropriate liquid material selection, the effect of refractive index ratio, r = n2/n1, on beam steering was additionally studied. However, one considerable issue is the fact that the better beam steering, the more reflection loss. This is because both higher number of interfaces and larger refractive index ratio make more reflection at each of the interfaces. Our reflectance analysis showed that the quad prism performs inferior to the double prism until α = ± 32°, while being of superior beam steering performance. To further reduce the solar energy loss through the quad prism, a modified configuration is proposed with a thin film added to the interfaces. 50 % of the total reflection was reduced. Our technology promises an alternative to a low-cost and high-efficiency solar tracking system capable of beam steering as wide as ± 75° and reflection loss as low as 4.5%, during all daily tracking of the sun.

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Tungsten Nanowire Metamaterials as Selective Solar Thermal Absorbers by Excitation of Magnetic Polaritons

Journal of Heat Transfer ◽

10.1115/1.4034845 ◽

2017 ◽

Vol 139 (5) ◽

Cited By ~ 11

Author(s):

Jui-Yung Chang ◽

Hao Wang ◽

Liping Wang

Keyword(s):

Conversion Efficiency ◽

High Efficiency ◽

Incident Angle ◽

Nanowire Array ◽

Geometric Parameters ◽

Radiative Properties ◽

Solar Thermal ◽

Fdtd Simulation ◽

Nanowire Diameter ◽

Solar Absorber

The present study focuses on nanowire-based metamaterials selective solar absorbers. Finite-difference time-domain (FDTD) simulation is employed for numerically designing a broadband solar absorber made of lossy tungsten nanowires which exhibit spectral selectivity due to the excitation of magnetic polariton (MP). An inductor–capacitor circuit model of the nanowire array is developed in order to predict the resonance wavelengths of the MP harmonic modes. The effects of geometric parameters such as nanowire diameter, height, and array period are investigated and understood by the sweep of geometric parameters, which tunes the MP resonance and the resulting optical and radiative properties. In addition, the optical properties and conversion efficiency of this nanowire-based absorber are both demonstrated to be insensitive on incidence angles, which illustrates the potential applicability of the proposed nanowire-based metamaterial as a high-efficiency wide-angle selective solar absorber. The results show that the nanowire-based selective solar absorber with base geometric parameters can reach 83.6% of conversion efficiency with low independence of incident angle. The results will facilitate the design of novel low-cost and high-efficiency materials for enhancing solar thermal energy harvesting and conversion.

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High-Efficiency Solar Power Supply Design

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.605-607.433 ◽

2012 ◽

Vol 605-607 ◽

pp. 433-437

Author(s):

Hong Yang ◽

Wen Qi Huang ◽

Zhen Fei Wang ◽

Long Guang Chen ◽

Yao Yin

Keyword(s):

Experimental Data ◽

Power Supply ◽

High Efficiency ◽

Incident Angle ◽

Tracking System ◽

Fresnel Lens ◽

Solar Panels ◽

Solar Module ◽

Charging System ◽

Voltage Current Characteristic

In order to improve the efficiency of solar module, we have designed the Fresnel lens concentrated system and charging system, their schematic diagrams are depicted detailed in this paper. The experimental data show that adding Fresnel lens parts can improve the solar panels' power from 130% to 200% and incident angle can affect solar panels' voltage current characteristic deeply. All of these results can give some support to design the tracking system.

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3D-Simulation of Topology-Induced Changes of Effective Permeability and Permittivity in Composite Materials

Journal of Nanomaterials ◽

10.1155/2007/80814 ◽

2007 ◽

Vol 2007 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

B. Hallouet ◽

R. Pelster

Keyword(s):

Composite Materials ◽

Effective Permeability ◽

Filling Factor ◽

Effective Permittivity ◽

Matrix Material ◽

Systematic Difference ◽

Material Parameters ◽

Effective Medium Model ◽

Permittivity And Permeability ◽

Induced Changes

We have performed 3D simulations of complex effective permittivity and permeability for random binary mixtures of cubic particles below the percolation threshold. We compare two topological classes that correspond to different spatial particle arrangements: cermet topology and aggregate topology. At a low filling factor off=10%, where most particles are surrounded by matrix material, the respective effective material parameters are indistinguishable. At higher concentrations, a systematic difference emerges: cermet topology is characterized by lower effective permittivity and permeability values. A distinction between topological classes might thus be a useful concept for the analysis of real systems, especially in cases where no exact effective-medium model is available.

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