- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A non-singular transformation optics invisibility cloak by combining with scattering cancellation.
摘要： A mechanism-based method to suppress the transformation optics cloaking singularities is proposed. Using the invariance nature of the Maxwell’s equations, instead of a point, a scattering cancellation cloaked circle is used as the virtual space for the transformation. The advantages of the proposed method includes non-singular constitutive parameters and significantly reduced variation range. Singularity removal is proved analytically while invisibility is demonstrated numerically using COMSOL Multiphysics.
关键词： Transformation Optics,Non-Singular Invisibility Cloaks,Invisibility Cloaks,Mantle Cloaking
更新于2025-09-23 15:22:29
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Electromagnetic wave cloaking and scattering around an antiresonance-resonance symmetrical pair in the frequency domain
摘要： Cloaking and scattering cancellation of electromagnetic waves have attracted much attention since they allow control of rf and light waves and are of scientific interest. The analytical results demonstrated in this paper reveal that plasmonic cloaking, which is one of the schemes for scattering cancellation, occurs in the vicinity of Tonks-Dattner resonances in the frequency domain, where resonances enhance wave scattering. This antiresonance-resonance pair for cloaking and scattering is cross-correlated by the symmetrical locations above and below the electron plasma frequency, respectively. However, the cloaking effect is almost independent of electron collisions with neutral particles, whereas scattering at resonance is fairly sensitive to them, leading to unclear resonance. An experimental verification of this analytical prediction is performed for the cloaking effect on working points passing through the cloaking condition and approaching resonance, which is dynamically controlled by changing the electron density. Numerical calculations based on a model configuration similar to the experimental setup confirm scattering cancellation and an increase in scattering as the points get close to the resonance condition. These results are direct evidence of scattering cancellation with a uniform epsilon-near-zero material and demonstrate the effectiveness of plasma as a cloaking material.
关键词： plasma,electromagnetic cloaking,scattering cancellation,Tonks-Dattner resonances,epsilon-near-zero material
更新于2025-09-23 15:22:29
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A flexible procedure to avoid the boundary materials singularities in 2D transformation-based cloaks
摘要： An out-of-plane coordinate transformation can avoid singular materials in a two-dimensional electromagnetic cloak. Based on numerical simulations of elliptical cylinders, in this paper we show that the use of two different constants to define the out-of-plane stretching can result in anisotropic materials with lower values and yet with a better scattering reduction for a given incident wave direction.
关键词： scattering cross-width,Cloaking,coordinate transformation,electromagnetic metamaterials
更新于2025-09-23 15:21:21
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Compact Cross-coupled Quarter-mode SIW Bandpass Filters with Different Locations of Input and Output Ports
摘要： We propose an effective approach for optimal wideband cloaking of objects with arbitrary shapes exploiting adjoint sensitivity analysis. Our method optimizes the voxel-by-voxel constitutive parameters of an anisotropic cloak resulting in a large number of optimizable parameters. The associated sensitivities of a wideband cloaking objective function are efficiently estimated using our in-house anisotropic adjoint variable method (AVM) simulator. Only one adjoint simulation is needed regardless of the number of required sensitivities. A gradient-based optimization algorithm utilizes the available sensitivity information to iteratively improve the wideband cloaking objective function and to determine the constitutive parameters of the optimal cloak.
关键词： optimization,transmission line matrix (TLM) method,cloaking,Adjoint variable method (AVM)
更新于2025-09-23 15:21:01
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Stable 3D FDTD method for arbitrary fully electric and magnetic anisotropic Maxwell's equations
摘要： We have developed a new fully anisotropic 3D FDTD Maxwell solver for arbitrary electrically and magnetically anisotropic media for piecewise constant electric and magnetic materials that are co-located over the primary computational cells. Two numerical methods were developed that are called nonaveraged and averaged methods, respectively. The nonaveraged method is first-order accurate, while the averaged method is second-order accurate for smoothly-varying materials and reduces to first order for discontinuous material distributions. For the standard FDTD field locations with the co-location of the electric and magnetic materials at the primary computational cells, the averaged method required development of the different inversion algorithms of the constitutive relations for the electric and magnetic fields. We provide a mathematically rigorous stability proof followed by extensive numerical testing that includes long-time integration, eigenvalue analysis, tests with extreme, randomly placed material parameters, and various boundary conditions. For accuracy evaluation, we have constructed a test case with an explicit analytic solution. Using transformation optics, we have constructed complex, spatially inhomogeneous geometrical object with fully-anisotropic materials and a large dynamic range of ?? and ??, such that a plane wave incident on the object is perfectly reconstructed downstream.
关键词： fully anisotropic,eigenvalue analysis,3D FDTD,stability,cloaking
更新于2025-09-23 15:21:01
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[IEEE 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - Shenzhen, China (2019.11.25-2019.11.27)] 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - High-efficiency GaN-based LED with patterned SiO <sub/>2</sub> passivation layer and discontinuous current block layer
摘要： We propose an effective approach for optimal wideband cloaking of objects with arbitrary shapes exploiting adjoint sensitivity analysis. Our method optimizes the voxel-by-voxel constitutive parameters of an anisotropic cloak resulting in a large number of optimizable parameters. The associated sensitivities of a wideband cloaking objective function are efficiently estimated using our in-house anisotropic adjoint variable method (AVM) simulator. Only one adjoint simulation is needed regardless of the number of required sensitivities. A gradient-based optimization algorithm utilizes the available sensitivity information to iteratively improve the wideband cloaking objective function and to determine the constitutive parameters of the optimal cloak.
关键词： cloaking,transmission line matrix (TLM) method,Adjoint variable method (AVM),optimization
更新于2025-09-19 17:13:59
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Zirconium Nitride for Plasmonic Cloaking of Visible Nanowire Photodetectors
摘要： Light scattered by a photodetector disturbs the probing field, resulting in noise. Cloaking is an effective method to reduce this noise. Here we investigate theoretically an emerging plasmonic material, zirconium nitride (ZrN), as a plasmonic cloak for silicon (Si) nanowire-based photodetectors and compare it with a traditional plasmonic material, gold (Au). Using Mie formalism, we have obtained the scattering cancelation across the visible spectrum. We found that ZrN cloaks produce a significant decrease in the scattering from bare Si nanowires, which is 40% greater than that obtained with Au cloaks in the wavelength region of 400–500 nm. The scattering cancelations become comparable at 550 nm, with Au providing a better scattering cancelation compared to ZrN over the wavelength region of 600–700 nm. To include the absorption and provide a measure of overall performance on noise reduction, a figure of merit (FOM), defined as the ratio of the absorption efficiency and the scattering efficiency of the cloaked nanowire to that of the bare Si nanowire, was calculated. We show that the optimized ZrN cloak provides up to 3 times enhancement of the FOM over a bare Si NW and a 60% improvement over an optimized Au-cloaked NW, in the wavelength region of 400–500 nm. An optimized Au-cloaked NW shows up to 17.69 times improvement in the wavelength region of 600–700 nm over a bare Si NW and up to a 2.7 times improvement over an optimized ZrN-cloaked NW. We also predicted the optimal dimensions for the cloaked NWs with respect to the largest FOM at various wavelengths between 400 and 650 nm.
关键词： Plasmonic cloaking,Core-shell,Nanowires,Emerging plasmonic materials,Zirconium nitride,Scattering cancelation
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Extended Path-finding RWA Algorithm Based on ACO in Optical Satellite Network
摘要： We propose an effective approach for optimal wideband cloaking of objects with arbitrary shapes exploiting adjoint sensitivity analysis. Our method optimizes the voxel-by-voxel constitutive parameters of an anisotropic cloak resulting in a large number of optimizable parameters. The associated sensitivities of a wideband cloaking objective function are efficiently estimated using our in-house anisotropic adjoint variable method (AVM) simulator. Only one adjoint simulation is needed regardless of the number of required sensitivities. A gradient-based optimization algorithm utilizes the available sensitivity information to iteratively improve the wideband cloaking objective function and to determine the constitutive parameters of the optimal cloak.
关键词： cloaking,transmission line matrix (TLM) method,optimization,Adjoint variable method (AVM)
更新于2025-09-19 17:13:59
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Electromagnetic Scattering for Complex Shape Objects with and without Cloaking
摘要： The problem of scattering electromagnetic field modeling on complex objects with and without using radio absorbing coating is considered. Based on existing methods field calculating for complex shape objects and elementary facets a computer program has been developed. It takes into account the field scattered by smooth part of the object, by edges, re-reflections between different parts of the object and contribution of cloaking. The proposed approach allows effectively calculating the field for complex shape objects with different radio absorbing coating without updating the geometric model of the object. The simulation results for elementary targets are compared with the theoretical data for the field scattered by these objects. The developed method results matches with the theoretical data.
关键词： electromagnetic scattering,complex shape object,facet,cloaking,radio absorbing coating
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Recent Developments in the Design of Waveform-Selective Mantle Cloaks for Antenna Applications
摘要： In this contribution, we investigate the idea of a waveform selective cloak for antenna applications. To achieve this purpose, a conventional mantle cloak designed to hide a wire antenna is loaded with a lumped-element circuit. Exploiting the peculiar time-domain response of the circuit, the cloak is able to modify its behavior either as an invisibility device or a perfect electric conductor when the impinging signal switches from a pulse (PW) to a continuous (CW) wave, respectively. The proposed configuration paves the way to a new generation of tunable and reconfigurable cloaking devices for antenna applications.
关键词： waveform-selective cloak,antenna applications,tunable cloaking devices,lumped-element circuit,mantle cloak
更新于2025-09-10 09:29:36