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Ring-shaped optical coherence lattice distribution produced by light waves on scattering
摘要： With the help of Markov approximation, a layer-structured random medium which may produce a far-zone scattered field with ring-shaped optical coherence lattice (RSOCL) distributions is discussed, and properties of the RSOCL produced by such a medium are investigated. It is shown from the distribution of the RSOCL that the diameter of each Gaussian profile lobe, the radial distance of all adjacent lobes, the number of the rings, the number of the lobe of each ring, and the radial distance of the array rings can be properly controlled by adjusting structural parameters of the scattering medium. Furthermore, by a method of superposition of several non-negative weight functions, a RSOCL with tunable lobes intensity distribution was obtained.
关键词： Light wave scattering,light field manipulating,spectral density
更新于2025-09-23 15:21:01
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Scattering due to uniaxial anisotropic chiral medium-coated PEC cylinder with conducting helix loading
摘要： A perfect electrically conducting (PEC) cylinder (having a circular cross-section) encapsulated with uniaxial anisotropic chiral medium was studied emphasizing the features of scattering. A conducting sheath helix structure having a varying orientation with respect to the optical axis (or pitch angle) was assumed to be at the outermost surface. This allows alterations in scattering patterns. The echo width of the structure was evaluated under the assumption of parallel polarized oblique incidence of waves. The effect on scattering was evaluated under varying chirality and permittivity of the coating medium along with the variations in the helix pitch angle. The obtained results are compared with those achieved by replacing the chiral coating with a simple anisotropic kind of medium (without chirality).
关键词： anisotropic chiral mediums,complex helical structures,Wave scattering
更新于2025-09-19 17:15:36
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Coupled Plasmon Oscillations in a Cluster Consisting of Three Silver Nanocylinders with Different Diameters
摘要： 2D problem of the diffraction of the TM plane electromagnetic wave by a cluster consisting of three self-similar silver nanocylinders with different sizes is considered. Rigorous numerical procedures are used to study quasi-static plasmon resonances in such a cluster. Frequency characteristics of the scattering cross section and spatial structure of the field in the vicinity of the cylinders are calculated for different angles of incidence of the plane wave, self-similarity coefficients, and diameters of cylinders. It is shown that an increase in the distance between the cylinders is accompanied by degeneration of the resonances of scattering cross section. When real loss of silver is taken into account, electric field at the exit of the cluster cannot be amplified by a factor of greater than 10.
关键词： plasmon resonances,electric field amplification,diffraction,silver nanocylinders,TM plane electromagnetic wave,scattering cross section
更新于2025-09-11 14:15:04
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Scatterer Surface Design for Wave Scattering Application
摘要： In this paper, radio wave scattering is considered and an optimal scatterer surface is realized. For this purpose, an ultra-wideband and high-efficiency polarization converter unit-cell is proposed. Here, the proposed polarization converter unit-cell and its mirror are combined to provide 180? phase difference for scattering purposes. The desired combination of unit-cells which produces uniform scattering pattern and maximum wave attenuation achieved employing group search optimization (GSO) algorithm. For the problem at hand, the GSO optimization algorithm is presented in bi-level format including master and slave levels. Simulation and experimental results showed that the 10 dB bandwidth of normalized RCS reduction is achieved in ultra-wideband ranging from 5.5 GHz to 20.51 GHz with a fractional bandwidth of 115%, assuring a favorable performance of the proposed method. In addition, a wide angle bistatic RCS reduction over a wide frequency band is attained.
关键词： scatterer structure,ultra-wideband,radio-wave scattering,Polarization rotation (PR)
更新于2025-09-10 09:29:36
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SCATTERING AND TRANSMISSION OF WAVES IN MULTIPLE RANDOM ROUGH SURFACES: ENERGY CONSERVATION STUDIES WITH THE SECOND ORDER SMALL PERTURBATION METHOD
摘要： Energy conservation is an important consideration in wave scattering and transmission from random rough surfaces and is particularly important in passive microwave remote sensing. In this paper, we study energy conservation in scattering from layered random rough surfaces using the second order small perturbation method (SPM2). SPM2 includes both first order incoherent scattering and a second order correction to the coherent fields. They are combined to compute the total reflected and transmitted powers, as a sum of integrations over wavenumber kx, in which each integration includes the surface power spectra of a rough interface weighted by an emission kernel function (assuming the roughness of each interface is uncorrelated). We calculate the corresponding kernel functions which are the power spectral densities for one-dimensional (1D) surfaces in 2D scattering problems and examine numerical results for the cases of 2 rough interfaces and 51 rough interfaces. Because it is known that the SPM when evaluated to second order conserves energy, and it can be applied to second order for arbitrary surface power spectra, energy conservation can be shown to be satisfied for each value of kx in the kernel functions. The numerical examples show that energy conservation is obeyed for any dielectric contrast, any layer configuration and interface, and arbitrary roughness spectra. The values of reflected or transmitted powers predicted, however, are accurate only to second order in small surface roughness.
关键词： roughness spectra,wave scattering,random rough surfaces,SPM2,transmission,passive microwave remote sensing,layered random rough surfaces,small perturbation method,power spectral densities,Energy conservation,dielectric contrast
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Kiev (2018.7.2-2018.7.5)] 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Modeling of Electromagnetic Wave Scattering and Propagation in the Presence of a Pre-Fractal PEC Strip Grating
摘要： Classes of one-dimensional self-similar fractals with variable Hausdorff–Besicovitch dimension are presented. They can be used in the pre-fractal modelling in electromagnetic and acoustic wave theory: wave scattering by pre-fractal gratings and wave propagation in pre-fractal systems of microstrip lines.
关键词： self-similar fractals,wave scattering,wave propagation,pre-fractal modelling,fractal dimension
更新于2025-09-09 09:28:46