The Experts below are selected from a list of 10764 Experts worldwide ranked by ideXlab platform
Weijia Wen - One of the best experts on this subject based on the ideXlab platform.
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tuning fabry perot resonances via diffraction evanescent Waves
Physical Review B, 2007Co-Authors: Bo Hou, Weijia Wen, Manzhu Ke, Zhengyou Liu, Jing Shi, Jun Mei, Ping ShengAbstract:By studying acoustic and Electromagnetic Wave Transmission through a periodic array of subWavelength holes or slits with various channel lengths, we demonstrate both experimentally and theoretically that diffraction evanescent Waves can play an important role in tuning the Fabry-Perot FP resonances. In particular, there can be total Transmission peaks at Wavelengths much below that of the Rayleigh-Wood limit, and FP resonances can occur for channel length 16% thinner than the half Wavelength. In addition, the FP resonance condition can be tuned via both the periodicity and area fraction of holes. As a function of the ratio between the periodicity and plate thickness, the FP resonance is smoothly linked to the surface-Wave-like mode induced by the periodic structure factor.
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Enhanced Transmission of Electromagnetic Waves through metamaterials
Applied Physics A, 2007Co-Authors: Bo Hou, Yang Leng, H. Wen, Weijia WenAbstract:This paper reviews our recent experimental and simulation results regarding the Electromagnetic Wave Transmission through three configurations of sandwiching structures of metamaterials: a metallic mesh sandwiched between two identical layers composed of split rings, metallic fractals, and fractal slits, respectively. We observed the enhanced Transmission of the Waves through these three types of sandwiching composites with respect to the opaque metallic mesh. The locations of the Transmission peaks in the spectrum are associated closely with the band characteristics of the sandwiching layer by appearing either on the left- or the right-hand side of its band.
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Electromagnetic Wave Transmission through subWavelength metallic meshes sandwiched between split rings
Applied Physics Letters, 2005Co-Authors: Bo Hou, He Wen, Yang Leng, Weijia WenAbstract:We report the extraordinary enhanced Transmission of microWaves through a subWavelength metallic mesh sandwiched between two identical split-ring arrays. Such split-rings/metallic mesh/split-rings structure demonstrates some unique Electromagnetic (EM) characteristics. It is found that the transmittances of EM Wave are significantly enhanced at some frequencies near the stop bands of the split rings. The theoretical simulation indicates that two different physical mechanisms dominate those Transmissions: negative refractive index effect and Electromagnetic Wave tunneling when EM Wave penetrates through negative permittivity media sandwiched between two high permittivity slabs.
Sae Chae Jeoung - One of the best experts on this subject based on the ideXlab platform.
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terahertz Electromagnetic Wave Transmission through random arrays of single rectangular holes and slits in thin metallic sheets
Physical Review Letters, 2007Co-Authors: D.h. Kang, K S Khim, Sae Chae JeoungAbstract:: We report on the observation of terahertz transparency in random arrays of the single rectangular holes and slits with the areal coverage of only 12%. The terahertz transparency occurs at the fundamental shape resonance of the rectangular holes and confirms the theoretical predictions of earlier works of Garcia-Vidal et al. [Phys. Rev. Lett. 95, 103901 (2005)] on single rectangular holes and of Ruan and Qiu [Phys. Rev. Lett. 96, 233901 (2006)] on random arrays of holes.
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Terahertz Electromagnetic Wave Transmission through random arrays of single rectangular holes and slits
2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007Co-Authors: Joong Wook Lee, Minah Seo, D.h. Kang, Sae Chae Jeoung, Q-han Park, Dai-sik KimAbstract:We have achieved the nearly perfect Transmission over 90% of random arrays that can be thought of as merely collective system of single rectangular holes with various length-to-width ratios and slits, using terahertz time domain spectroscopy. It is found that the terahertz transparency by the enhanced Transmission can be experimentally realized even in the areal coverage less than 12% at the fundamental shape resonance, provided that the shape is strongly asymmetric.
Bo Hou - One of the best experts on this subject based on the ideXlab platform.
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tuning fabry perot resonances via diffraction evanescent Waves
Physical Review B, 2007Co-Authors: Bo Hou, Weijia Wen, Manzhu Ke, Zhengyou Liu, Jing Shi, Jun Mei, Ping ShengAbstract:By studying acoustic and Electromagnetic Wave Transmission through a periodic array of subWavelength holes or slits with various channel lengths, we demonstrate both experimentally and theoretically that diffraction evanescent Waves can play an important role in tuning the Fabry-Perot FP resonances. In particular, there can be total Transmission peaks at Wavelengths much below that of the Rayleigh-Wood limit, and FP resonances can occur for channel length 16% thinner than the half Wavelength. In addition, the FP resonance condition can be tuned via both the periodicity and area fraction of holes. As a function of the ratio between the periodicity and plate thickness, the FP resonance is smoothly linked to the surface-Wave-like mode induced by the periodic structure factor.
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Enhanced Transmission of Electromagnetic Waves through metamaterials
Applied Physics A, 2007Co-Authors: Bo Hou, Yang Leng, H. Wen, Weijia WenAbstract:This paper reviews our recent experimental and simulation results regarding the Electromagnetic Wave Transmission through three configurations of sandwiching structures of metamaterials: a metallic mesh sandwiched between two identical layers composed of split rings, metallic fractals, and fractal slits, respectively. We observed the enhanced Transmission of the Waves through these three types of sandwiching composites with respect to the opaque metallic mesh. The locations of the Transmission peaks in the spectrum are associated closely with the band characteristics of the sandwiching layer by appearing either on the left- or the right-hand side of its band.
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Electromagnetic Wave Transmission through subWavelength metallic meshes sandwiched between split rings
Applied Physics Letters, 2005Co-Authors: Bo Hou, He Wen, Yang Leng, Weijia WenAbstract:We report the extraordinary enhanced Transmission of microWaves through a subWavelength metallic mesh sandwiched between two identical split-ring arrays. Such split-rings/metallic mesh/split-rings structure demonstrates some unique Electromagnetic (EM) characteristics. It is found that the transmittances of EM Wave are significantly enhanced at some frequencies near the stop bands of the split rings. The theoretical simulation indicates that two different physical mechanisms dominate those Transmissions: negative refractive index effect and Electromagnetic Wave tunneling when EM Wave penetrates through negative permittivity media sandwiched between two high permittivity slabs.
Yijun Feng - One of the best experts on this subject based on the ideXlab platform.
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Dynamic control of asymmetric Electromagnetic Wave Transmission by active chiral metamaterial.
Scientific reports, 2017Co-Authors: Ke Chen, Yijun Feng, Li Cui, Junming Zhao, Tian Jiang, Bo ZhuAbstract:The asymmetric Transmission of Electromagnetic (EM) Wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM Wave Transmission at microWave frequencies using planar metamaterial of deep subWavelength thickness incorporated with active components of PIN diodes. The asymmetric Transmission of linearly polarized EM Wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric Transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full Wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM Wave propagation, as well as to facilitate EM device integration to create diverse functionalities.
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Passive Metasurface for Reflectionless and Arbitary Control of Electromagnetic Wave Transmission
IEEE Transactions on Antennas and Propagation, 2015Co-Authors: Bo O. Zhu, Yijun FengAbstract:Electromagnetic (EM) Wave propagation control is an important issue for both science and engineering. A metasurface is an artificial surface composed of electrically small scatterers. Of late, metasurfacing has been an emerging and promising technique for controlling Wave propagation. Traditional metasurfaces mainly employ surface reactances and generally reflect Waves when manipulating Wave Transmission or refraction. In this paper, a passive metasurface employing both surface reactance and positive surface resistance is proposed, which can not only manipulate Wave Transmission magnitude and phase independently and fully but also suppress Wave reflection simultaneously. Furthermore, reflectionless refraction can also be achieved with the proposed passive metasurface. The complete design theory is established for the passive metasurface. Theoretical analysis, prototypes, simulation, and experimental validation are demonstrated. The reflectionless feature of a passive metasurface is important for avoiding multiple Wave reflections and interference between stages in EM systems. It also enables novel Wave Transmission cascade manipulation and may have potential applications in highly directive radiation.
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Dual-band asymmetric Electromagnetic Wave Transmission for dual polarizations in chiral metamaterial structure
Applied Physics B, 2014Co-Authors: M.s. Zhang, Tian Jiang, Junming Zhao, Bo Zhu, Yijun FengAbstract:In this paper, we propose a chiral metamaterial structure that enables dual-band asymmetric Transmission effect for different linearly polarized Electromagnetic Waves. The metamaterial is composed of metallic spirals with two split-ring resonators sandwiching a dielectric slab and connecting with via hole. Strong one-way Transmission of two orthogonally polarized Waves at different frequency bands has been confirmed through both full-Wave simulation and test on fabricated prototype at the microWave band. Analysis also shows such asymmetric Transmission can be attributed to the induced asymmetric current distributions in the spiral that support strong polarization conversion and cross-polarization Transmission. By scaling down the metamaterial structure, the concept could also be utilized at other frequency bands, such as submillimeter or even terahertz band and find applications in designing one-way Electromagnetic Wave devices or polarization spectral filters.
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asymmetric Electromagnetic Wave Transmission of linear polarization via polarization conversion through chiral metamaterial structures
Physical Review B, 2012Co-Authors: Ci Huang, Yijun Feng, Junming Zhao, Zhengbin Wang, Tian JiangAbstract:In this paper a kind of chiral metamaterial structure is proposed that can achieve asymmetric Transmission for forward and backward propagations of linearly polarized Electromagnetic (EM) Waves. We first give a theoretical analysis on a kind of bilayered metamaterial structure with specific structure asymmetry that enables the asymmetric EM Wave Transmission only for linear polarization. Then by constructing a proof-of-concept metamaterial sample with twisted split ring resonator patterns on both sides of a dielectric slab, we demonstrate substantial asymmetric Transmission for linear polarizations, but none for circular polarizations through full-Wave simulation and measurement at microWave frequency. Strong optical activity is found in the chiral metamaterial indicating that the intriguing asymmetric Transmission is caused by the directional difference in cross polarization conversion. By scaling down the structure, the proposed concept could be utilized in other frequency bands, such as terahertz and optical range.
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Loss and retardation effect on subWavelength imaging by compensated bilayer of anisotropic metamaterials
Journal of Applied Physics, 2006Co-Authors: Yan Chen, Xiaohua Teng, Ying Huang, Yijun FengAbstract:We analyze the subWavelength imaging using compensated bilayer of anisotropic metamaterials and study the material loss and retardation effect on the image properties. Through rigorous analysis of the Electromagnetic Wave Transmission and numerical calculations of the Electromagnetic field distribution, we demonstrate that the anisotropic bilayer lens exhibits a decreased sensitivity to material loss and retardation, therefore has a better image with subWavelength resolution than that of the isotropic perfect lens configuration. We find that this is due to the fact that the inhomogeneous evanescent Waves that are responsible for image resolution beyond the diffraction limit have been converted to propagating Waves in the anisotropic bilayer, resulting in less sensitive to material loss and retardation.
P. P. Sverbil - One of the best experts on this subject based on the ideXlab platform.
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Finite-Difference Time-Domain Technique for Gyroelectric Material Structure Simulation Using Recursive Convolutions in Polarization
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: A. V. Friman, A. A. Gorbatsevich, P. P. SverbilAbstract:A gyrotropic material handling method is proposed. Our technique does not require modification of the finite-difference time-domain stepping algorithm, and the gyroelectric phenomenon can be treated as a variation of material polarization. The simulation of Electromagnetic Wave Transmission through a test gyroelectric structure of a magnetized plasma layer is presented and compared with the analytical solution. An open source implementation is presented.