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An analytical study of the early-time surface current density induced on a perfectly conducting circular cylinder excited by a parallel line source carrying a δ-function current has been carried out. Expressions of the current density for both the shadow and the illuminated region are obtained. Numerical results are presented to illustrate the variation of the surface current density with time for...
The equivalence principle and the moment method which was previously employed in the solution of single-step waveguide discontinuities, is extended to solve for the field and the scattering matrix coefficients at the junctions of multiple-step discontinuities. Scattering matrix coefficients are computed for representative double-step discontinuities and frequencies. The method is simple and straightforward,...
Early-time current response of a conducting cylinder to a step-function electromagnetic plane wave has been already thoroughly studied [l]-[4]. In this paper, we consider the early-time response of a perfectly conducting circular cylinder to cylindrical electromagnetic waves generated by a parallel filament carrying a unit-step current. The geometry of the problem is shown in Fig. 1. The mathematical...
By expanding the incident and scattered electric fields in terms of an appropriate set of vector spheroidal eigenfunctions, an exact solution is obtained to the problem of scattering of a plane electromagnetic wave by two perfectly conducting prolate spheroids of arbitrary orientation. The boundary conditions are imposed by expressing the field scattered by one spheroid in terms of the spheroidal...
Bistatic and backscattering cross sections associated with the field scattered by two perfectly conducting prolate spheroids of arbitrary orientation, are calculated for an arbitrary polarization and direction of propagation of the incident, uniform plane electromagnetic wave. Numerical results are presented for spheroids with various axial ratios and orientations.
General unsymmetric systems of linear algebraic equations are modeled by linear electric circuits using a procedure previously developed for symmetric systems [1]. Augmented symmetric systems are constructed from the original unsymmetric ones and then the modeling technique based on the node-voltage method is applied. The unknowns of a system of equations are simply obtained by measuring the nodal...
Formulations of electromagnetic wave scattering by lossy dielectric bodies in terms of volume integral equations require a large amount of computation due to the volume distribution of unknown sources and some of them are unreliable when applied to dielectric bodies with large values of relative permittivity. The analysis of wave scattering by coupled surface integral equations reduces the dimensionality...
Passive resistive circuit models are used to derive bounds for the solution of strictly diagonally dominant symmetric systems of algebraic equations with all of the off-diagonal entries being of the same sign and all diagonal and right-hand side entries being of opposite sign. The values of the unknowns are in an interval obtained from [0,1] by performing an appropriate scaling of the right-hand side...
The normalized backscattering and bistatic cross sections for a linear array of N dielectric spheres are computed and presented graphically over wide ranges of permittivity, separation, size, and angle of incidence. The results show reduction in the normalized backscattering and bistatic cross sections for certain choices of permittivity relative to arrays of perfectly conducting spheres of same dimensions...
The problem of multiple scattering of a plane electromagnetic wave incident on N dielectric spheres is investigated by two methods. The first is based on the multipole expansion method which gives analytic solution by using the spherical vector addition theorem to impose the boundary condition, while the second is an approximate method valid for relatively small spheres. Expressions for the total...
Construction of field lines for vector fields can be performed by a variety of analytical or graphical methods. Except for a small number of simple geometries, where closed analytical expressions can be obtained, the shape of the field lines is determined by numerical computation or evaluated approximately by physical modelling techniques [1]. In this paper, we consider irrotational vector fields...
In this paper, an approximate method is described for solving the problem of electromagnetic scattering by two coaxial prolate spheroids, with their major axes along the common axis. The incident wave is considered to be a monochromatic uniform plane electromagnetic wave of arbitrary polarization, and angle of incidence. The method is based on the exact solution to scattering of a plane wave by a...
Image fusion techniques are being developed in order to generate an image which is superior to all the input images obtained by using various methods, from certainty and/or resolution points of view. These techniques have numerous applications in image processing, in general, and in biomedical imaging, in particular, where, for the same object various imaging systems produce images that have different...
Matrix series related to the solution of systems of linear algebraic equations are derived starting from the solution of a special type of a linear system of differential equations of the first order. The convergence of these series is adequate for computing efficiently approximate solutions of large systems of algebraic equations.
The first n-1 equations of a general n-by-n linear algebraic system are first made homogeneous. Then, the first unknown is eliminated from the equations 2, 3, …, n-1, with the n-th equation kept in its original form. A first solution of the equations 2 to n-1 and of the n-th equation is obvious. If a second, independent solution of these equations is found, the solution of the original system will...
A novel formulation of the boundary integral equation for the magnetic vector potential is presented, where its normal component is imposed to be zero while, instead of enforcing its tangential component, only the circulations of the potential are imposed along any closed paths on the boundary. When the boundary is modelled to be a perfect conductor, these circulations are equal to 0. It is proposed...
Inside the ferromagnetic bodies the magnetic field is determined by applying the Finite Element Method (FEM) with a Dirichlet boundary condition for the magnetic potential. The resulting tangential component of the field intensity is used as boundary condition for the exterior field problem whose solution is obtained by the Boundary Element Method (BEM) which provides the new boundary condition for...
The concept of the minimization of the distance to the solution point is introduced for the iterative solution of the general systems of linear algebraic equations. Search directions are constructed using combinations of the normals to the hyperplanes represented by the system equations.
Transmission line structures are commonly found in electrical power delivery systems. Efficient transient simulations of transmission line networks are important for characterization of power system performance. Conventionally, transients on power transmission lines are computed using time domain techniques such as PSCAD simulator [1] and the computational effort associated is generally high. In the...
The analysis of induced currents in conducting bodies due to the presence of an external magnetic field variable with time is necessary in numerous areas of applied electromagnetics, such as induction heating, eddy-current braking, electromagnetic shielding and electromagnetic levitation. An accurate study of the induced currents requires the field solution for both the inside and outside of the conductor...
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