Diffraction of a plane surface electromagnetic wave incident on a half plane

An integral representation and asymptotic expressions are derived for the diffraction field produced at an arbitrary angle of incidence on a half-plane representing an impedance. Some features of the field are discussed.     

Diffraction of electromagnetic plane wave by an infinitely long conducting strip on dielectric slab

Diffraction of electromagnetic plane wave by an infinitely long conducting strip which is placed on a dielectric slab of finite thickness is formulated rigorously. Both the principal polarizations have been considered. The method of analysis is Kobayashi potential. Imposition of boundary conditions result in dual integral equations. These dual integral equations are reduced to matrix equations with infinite number of unknowns. The elements of the matrix equations are given in terms of infinite integrals. These integrals are hard to solve analytically, so computed numerically. Diffracted far field patterns for different angle of incidence have been computed. Current distributions on the strip are also presented. We have compared our field patterns with those of obtained through physical optics. The agreement is good.     

Diffraction of a plane electromagnetic wave by a slot in a conducting screen with a transverse dielectric layer

The problem of diffraction of a plane electromagnetic wave by a slot in a planar perfectly conducting arbitrary thick screen with an infinite planar dielectric layer passing through the slot transversely to the screen is solved rigorously. In each of the field existence domains (two domains on either side of the screen and the interior of the slot), the solution is represented as an expansion in piecewise harmonic or exponential modes that allow for reflection and refraction at the boundaries of the dielectric layer. It is found that a set of functions describing such modes is complete enough to construct a solution satisfying all boundary conditions of the diffraction problem. The procedures of solution construction for the case at hand and for the same diffraction structure without the dielectric layer are compared.     

Diffraction of a plane electromagnetic wave at a schwarzschild black hole

Using the technique of Debye potentials a rigorous solution of the diffraction problem is given as a superposition of an incident wave, strongly connected with the Coulomb scattering wave function, and a scattered wave, which is purely outgoing for large distances. The solution fulfils the boundary conditions to be the light of a very distant star and to be purely ingoing at the Schwarzschild horizon. The phase shifts of the partial waves are evaluated in the WBK approximation.     

Diffraction of an electromagnetic wave on the finite lattice of carbon nanotubes-vibrators located at dielectric interfaces

A solution of the boundary problem on electromagnetic wave diffraction on a lattice of carbon nanotubes-vibrators is reduced to the solution of a set of integrodifferential equations, whose kernels are represented as a Fourier integral. Such representation of kernels makes it possible to easily overcome solution problems related to their singularities and reduce the computation time by one order of magnitude. Integrodifferential equations are solved using the Galerkin method with a Chebyshev basis. The effect of a substrate on amplitude-frequency characteristics and the scattering pattern of carbon nanotube antennas is studied. Both the resonance frequency and the amplitude of a scattered field are shown to increase in the case of approaching nanovibrators. The amplitude dependence on the number of vibrators is nonlinear.     

Transmission of a Transient electromagnetic plane wave through a grating of circular cylinders

An analysis of the transmission of a transient electromagnetic plane wave through a grating formed by an infinite array of circular cylinders is presented. Emphasis is placed on the transient shielding characteristics of the grating for various cylinder spacings and angles of incidence. The transient results are obtained by first obtaining analytical experssions for the fields in the frequency domain and then performing a numerical inverse Fourier transformation. Some physical interpretations of the shielding effectiveness of the grating are given.     

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.     

Diffraction of a plane electromagnetic wave by a cylindrical wedge with a rounded apex

We reduce the rigorously formulated problem of diffraction of a plane electromagnetic wave by a perfectly conducting cylindrical wedge with a rounded apex to solving the system of linear algebraic equations of the second kind for unknown coefficients of the Fourier expansions of the diffracted-field components. The expansion coefficients are determined analytically in the long-wavelength approximation. The results of calculations of the diffracted field in the far zone are presented with a given accuracy in the case of an E-polarized wave. It is shown that the rounding of the apex of a cylindrical wedge leads to an increase in the backscattering coefficient of the structure in the long-wavelength range. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 5, pp. 447–451, May 2008     

Symmetric electromagnetic waves in a dielectric coaxial line

On the basis of a solution of the Maxwell equations the configuration of electromagnetic fields of symmetric types of oscillations in a dielectric coaxial line is found. The expressions for power density for both symmetric and hybrid waves are obtained. The direction of power density coincides with the axis of various axial symmetric dielectric structures. The dependences of phase speeds of electric and magnetic waves on frequencies of radiation are presented. The frequency range in which only the lowest index symmetric waves propagate is found. At frequencies higher than critical, discrete symmetric modes of oscillation exist. The energy is transmitted mainly inside the dielectric rod, and the power density at the axis is equal to zero.