Diffraction Of Plane Electromagnetic Wave Research Articles

A new approach in electromagnetic plane wave diffraction by two concentric slotted cylinders with variably placed slits: E and H polarized cases

The study investigates the electromagnetic plane wave diffraction by two concentric slotted cylinders with variably placed slits. Unlike the previous studies, the effect of rotation on the resonance characteristics and near-field distributions is analyzed in the present work, which is not studied yet. The study focuses on diffraction by both E- and H-polarized plane waves. A semi-analytical method is preferred to obtain the physical properties such as resonances and near and far-field radiation patterns. The advantage of the method is to employ the analytical and numerical tools together. Due to having both E- and H-polarized plane waves, Dirichlet and Neumann Boundary conditions are considered and analyzed, respectively. After obtaining the mathematical expressions for the current density, near and far-field, and total radar cross-section, the different results are compared with the Method of Moment and the Method of Auxiliary Sources. The comparison demonstrates that the proposed method coincides with other well-known methods. The outcomes reveal that the aperture size and the rotation angle have a significant role in the radiation characteristics.

Diffraction by a Perfect Electromagnetic Conductor Half-Plane in an Anisotropic Plasma: An Integral Theory Approach

The diffraction of plane electromagnetic waves by a perfect electromagnetic conductor (PEMC) semi-infinite sheet which is embedded in an anisotropic medium is examined. The anisotropic region is modeled by a dielectric matrix. The external uniform magnetic field is taken as parallel to the edge of the semi-infinite sheet. Upon considering the H-polarized incident wave, the total scattered fields are obtained with the diffracted waves by using an integral theory which is associated with the scattered fields. The results are expressed in terms of the Fresnel functions. Thus, the wave behaviors at the transition boundaries are uniform. The solutions are compared numerically with the literature including limit values.

Electromagnetic plane wave diffraction by a cylindrical arc with edges: H-polarized case

An accurate hybrid method (numerical-analytical method) for the diffraction of H-polarized electromagnetic plane wave by perfectly electric conducting cylindrical bodies containing edges and a longitudinal slit aperture is proposed. This method is the combination of the Method of Moment and semi-inversion method. The current density function is expressed as the Chebyshev polynomials forming a complete orthogonal set of basis functions. Then, the initial problem is reduced to a system of linear algebraic equations. After inversion, the unknown coefficients are obtained. Then, near and far-field distributions, radar cross-sections are obtained. The resonances are observed for different values of the aperture size, radius of the arc, and the results are compared with previous outcomes.

ОПЕРАТОРНИЙ МЕТОД В ЗАДАЧІ ПРО ДИФРАКЦІЮ ПЛОСКОЇ ЕЛЕКТРОМАГНІТНОЇ ХВИЛІ НА КІЛЬЦЕВІЙ ЩІЛИНІ В ПЛОЩИНІ АБО НА КІЛЬЦІ

Purpose: The problem of a plane electromagnetic wave diffraction by an annular slot in the perfectly conducting zero thickness plane is considered. As a dual problem, the problem of diffraction by a perfectly conducting zero thickness ring is also considered. The paper aims at developing the operator method for the axially symmetric structures placed in free space. Design/methodology/approach: The problem is considered in the spectral domain. The scattered field is expressed in terms of unknown Fourier amplitudes (spectral functions). The annular slot is given as a unity of two simple discontinuities, namely of a disk and a circular hole in the plane, which interact with each other. The Fourier amplitude of the scattered field is sought as a sum of two amplitudes, the Fourier amplitude of the field of currents on the disk and Fourier amplitude of the field of currents on the perfectly conducting plane with circular hole. The operator equations are written for these amplitudes, which take into account the electromagnetic coupling of the disk and the hole in the plane. The equations use the reflection operators of a single isolated disk and a single hole in the plane. They are supposed to be known and can be obtained for example by the method of moments.The reflection operators can have singularities. After transformations, the equations are obtained, which are equivalent to the Fredholm integral equations of second kind and they can be solved numerically. Findings: The operator equations relative to the Fourier amplitudes of the field scattered by the discussed structure are obtained. The far zone scattered field for an annular slot and a ring for different values of parameters are studied. Conclusions: The rigorous solution of the problem of the electromagnetic wave diffraction by an annular slot in the plane and by a circular ring is obtained. The problem is reduced to the Fredholm integral equations of second kind. The far field distribution for different parameters is studied. The developed approach is an effective instrument for a number of problems of antenna technique to be solved. Key words: circular hole; disk; annular slot; ring; operator method; diffraction

The Diffraction by the Half-plane with the Fractional Boundary Condition

In this article, there is considered the electromagnetic plane wave diffraction by the half-plane with fractional boundary conditions. As a mathematical tool, the fractional calculus is used. The theoretical part is given based on which the near field, Poynting vector and energy density distribution are calculated. Interesting results are obtained for the fractional order between marginal values, which describes a new type of material with new properties. The results are analyzed.

Scattering of electromagnetic waves by an impedance sheet junction in anisotropic plasma

The diffraction of electromagnetic plane waves by the edge discontinuity of an impedance sheet junction, which is located in an anisotropic plasma, is investigated. The problem is solved by the integral theory of diffraction. The scattering integral is obtained from the scattered geometric optics wave. The diffracted fields are derived by the edge point evaluation of the scattering integral. The evaluated field expressions are analyzed numerically.

On the Scattering of Electromagnetic Waves by Cylindrical Bodies with Non-Coordinate Boundaries

Different variants of the problem of diffraction of plane electromagnetic wave by the cylindrical body are constructed and researched in the work. These problems are reduced to infinite sets of linear algebraic equations. The conductive bodies and dielectric bodies with thin conductive bands on the non-coordinate boundary are considered. The results of the computational experiment are presented.

Diffraction of Electromagnetic Waves by Multilayer Graphene Metasurfaces in the Terahertz Frequency Band

We perform mathematical modeling of diffraction of plane electromagnetic waves by multilayer metasurfaces comprised by elements of graphene nanoribbons. The modeling is based on solving the three-dimensional boundary value diffraction problem by three methods, specifically, those of self-contained units with Floquet channels, the volume integro-differential equation, and approximate boundary conditions. The coefficients of reflection, transmission, and absorption of s- and p-polarized waves by metasurfaces made of elements of rectangular graphene nanoribbons are calculated as functions of the frequency and the incidence angle for various values of the chemical potential with allowance for the geometric and dimensional effects in the terahertz frequency band. It is shown that at the resonant frequencies of the surface plasmon polariton, multilayer metasurfaces comprised by two graphene strips in an elementary cell on substrates, which contain layers of a dielectric and graphene, are electrically controlled efficient wideband terahertz absorbers and polarizers in the reflection regime that are insensitive to incidence angles.

Diffraction of plane electromagnetic waves by a resistive half-screen for skew incidence.

The scattering process of electromagnetic plane waves by a resistive half-screen is investigated for oblique incidence. First of all, it is shown that the existing solution in the literature is not correct, because the problem was solved by considering the normal components of the electromagnetic field, in terms of which the boundary conditions cannot be expressed. Instead of these, the components of the electric field, which is parallel to the edge discontinuity, are taken into account. The diffracted fields are obtained with the aid of the method of transition boundary. The uniform field expressions are obtained by using the Fresnel function. The behaviors of the total field and its subcomponents are analyzed numerically.

Coupled Plasmon Oscillations in a Cluster Consisting of Three Silver Nanocylinders with Different Diameters

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.

Scattering of electromagnetic waves by a perfect electromagnetic conductor half-screen

The diffraction of plane electromagnetic waves by a perfect electromagnetic conductor half-screen is investigated. The total geometrical optics fields are obtained by using the boundary conditions of a perfect electromagnetic conductor surface. A general relation is defined for the scattered fields in terms of waves by soft and hard surfaces. The total scattered field is derived by using this relation. Some numerical simulations are also given.

Plasmon Resonances in a Graphene Ribbon on a Finite-Size Dielectric Substrate

A 2D problem of the diffraction of plane electromagnetic wave by a graphene ribbon on a finitesize dielectric substrate is considered for the TM polarization. Rigorous numerical methods are used to calculate the scattering cross sections in the terahertz frequency range. It is shown that multipole resonances vanish in the scattering spectrum in the presence of a small substrate that represents a thin dielectric film.

Diffraction of electromagnetic plane wave by a slit in a homogeneous bi-isotropic medium

We investigated the diffraction of an electromagnetic plane wave by an infinite slit embedded in a homogeneous bi-isotropic medium. With the aim of deriving explicit expressions for the left- and right-handed Beltrami fields, we used the Fourier integral transform, the Wiener–Hopf technique and the steepest descent asymptotic method. The electric and magnetic fields, E and H, were determined from the Beltrami fields. Our graphical results indicate that the strength of both electric and magnetic fields reduces with the dissipation of bi-isotropic medium. While matching the diffraction pattern with the existing plane wave solution, the objective was, and is, to see how well spherical wave solution performs when it is developed for plane wave solution.

Quasi-static plasmon resonances in a graphene ribbon in the infrared range

The 2D problem of diffraction of a plane electromagnetic wave diffraction by a graphene ribbon is considered for the case of the TM polarization. Quasi-static plasmon resonanses are investigated with the use of rigorous numerical methods. The surface currents and scattering and absorption cross-sections are calculated. It is shown that, owing to the high Q-factor, multipole plasmon resonances appear not only in the near field but also in the far field.

Electromagnetic Plane Wave Diffraction by Loaded N-Slits on Thick Conducting Screen

Electromagnetic Plane Wave Diffraction by Loaded N-Slits on Thick Conducting Screen

Electromagnetic radiation security estimation on the residential building roof for cellular antenna

The work objective is to estimate the electromagnetic environment on the roof where a mobile system base station aerial is installed. The problem arises during maintenance, repair, and assembly operations for antenna-feeder devices. The evaluation problem for ecological assessment of the electromagnetic environment at a standard height of two meters above the roof is solved with the computational prediction method. Two strict models are used for electrodynamic simulation of energy flux density, i.e. a two ray model which describes the plane electromagnetic wave diffraction on the flat perfectly conducting roof surface, and finite models of the roof are described with the canonical problem on a wedge of infinite extent. The difference between the developed model and the known ones lies within the research possibility not only in the computational points but within a whole computational plane. In the simulation process, antenna emission characteristics can be set in a number of ways including those obtained from the radiation object specifications, as it is proposed in a well-known technique. The simulation results for energy flux density distribution in a horizontal plane within the roof space are given. Computational points are placed at the square grid nodes with the period of a quarter wavelength of the transmitter. A physical interpretation of the obtained results is given. A safety conclusion on the human presence on the roof with operating directional cel lular antenna of GSM standard is formulated.

Scattering of a plane electromagnetic wave by a perfectly conducting cylinder in a spherically symmetric radially inhomogeneous absorbing plasma formation

The problem of diffraction of a plane electromagnetic wave by an ideally conducting cylinder of a finite dimensions is solved by the edge wave method. The cylinder is situated in an absorbing radially inhomogeneous plasma formation. The edge wave method is applied for bodies situated in an inhomogeneous medium. Analytic expressions for determination of the dependence of the effective radar cross section of a cylinder that depend on the irradiation angle are obtained, and the corresponding graphical dependences are calculated on the basis of these dependences.

Closed form solution of electromagnetic wave diffraction problem in a homogeneous bi‐isotropic medium

In this study, the problem of wave scattering of an electromagnetic field in a homogeneous bi‐isotropic medium by a perfectly conducting strip is theoretically analyzed. The crux of the study is a rigorous construction of a closed form solution in the complex domain. A series solution of electromagnetic plane wave diffraction problem in terms of the eigenfunctions that happen to be the generalized Gamma functions is found. In the transformed domain, the scattered field is physically interpreted by computing the convergence history, and thereby, higher order accurate solution has been obtained in complex domain in closed form. Copyright © 2014 John Wiley & Sons, Ltd.

Influence of Fractal Embedding in Three-Dimensional Euclidean Space on Wave Propogation in Electro-Chromodynamics

In this paper two zero-dimensional com- pact sets with equal topological and fractal dimensions but embedded in Euclidean space by different ways are under study. Diffraction of plane electromagnetic wave propagated and reflected by fractal surfaces is considered for each of these compact sets placed in vacuum. It is obtained, that the embedding of com- pact influences on characteristics of wave in final state. Thus, the embedding of Cantor set in Euclidean space is additional property of a fractal which can be important both for applications of fractal electrodynamics and for physics of strong interactions.

Near-field light focusing by a slit array in a planar metal film with nonuniform slit dielectric material

We study the interference of evanescent electromagnetic waves generated from multi-slits in a metal film and demonstrate the anomalous bending of light at infrared frequencies due to negative refraction. We also calculate the diffraction of an incident plane electromagnetic waves by a metallic film with an arbitrary linear array of slits, slit separation, and slit dielectric material. In contrast to a double-convex shaped quartz lens, we show that a planar metallic film with a one-dimensional slit array can also focus polarized light in the near-field region when either the slit width or the slit dielectric material becomes spatially nonuniform.