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Jafri A.D.U.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University | Syed A.A.,Quaid-i-Azam University | Hongo K.,Nakashizu
Canadian Journal of Physics | Year: 2012

In this investigation, scattering from a perfectly conducting circular disk located on a grounded substrate has been studied rigorously. The incident field is a plane wave. The method of analysis uses a Kobayashi potential. The mathematical formulation produces dual integral equations (DIEs). These DIEs are solved by using the discontinuous properties of Weber-Schafheitlin's integral. After applying the projection, the resulting expressions reduce to matrix equations for expansion coefficients. The matrix elements are in the form of infinite integrals. The far-field patterns of the scattered field are computed for different incident angles and disk sizes for both E-and H-polarizations. To validate the results, we have computed the solution based on the physical optics approximation. The comparison of the results shows good agreement. © 2012 Published by NRC Research Press.


Imran A.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University | Hongo K.,Nakashizu
International Journal of Applied Electromagnetics and Mechanics | Year: 2010

In this paper, diffracting behavior of a perfectly electromagnetic conductor (PEMC) strip has been studied. Both the E- and H-polarization are considered. The method of analysis is Kobayashi Potential (KP). Imposition of boundary conditions results into dual integral equations (DIEs). These DIEs are solved by using the discontinuous properties of Weber-Schafheitlin's integral. The resulting expressions, finally, reduce to matrix equations with infinite number of unknowns whose elements are expressed in terms of infinite integrals. These integrals are hard to solve analytically so numerical simulation is done. Illustrative computations are presented for different parameters of interest especially the dependence of co-polarized and cross-polarized components on the admittance parameter. © 2010 - IOS Press and the authors.


Jafri A.D.U.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University | Hongo K.,Nakashizu
Progress in Electromagnetics Research | Year: 2012

In this investigation, scattering from a circular disk with surface impedance has been studied rigorously. The method of analysis is Kobayashi Potential (KP). The mathematical formulation yields the dual integral equations (DIEs). These DIEs are solved by using the discontinuous properties of Weber-Schafheitlin's integral. After applying the boundary conditions and projection, the resulting expressions, finally, reduce to matrix equations for expansion coefficients. The matrix elements are in the form of infinite integrals with single variable. These are then used to compute the values of expansion coefficients. The far field patterns of the scattered wave are computed for different incident angles and surface impedances for both E- and H-polarizations. To verify the results, we have computed the solution based on the physical optics approximation. The agreement between them is fairly good.


Hongo K.,Nakashizu | Jafri A.D.U.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University
Progress in Electromagnetics Research | Year: 2012

The scattering of electromagnetic spherical wave by a perfectly conducting circular disk is studied by using the method of Kobayashi Potential (abbreviated as KP method). The formulation of the problem yields the dual integral equations (DIE). The spherical wave is produced by an arbitrarily oriented dipole. The unknowns are the induced surface current (or magnetic field) and the tangential components of the electric field on the disk. The solution for the surface current is expanded in terms of a set of functions which satisfy one of a pair (equations for the magnetic field) of Maxwell equations and the required edge condition on the surface of the disk. At this stage we have used the vector Hankel transform. Applying the projection solves the rest of the pair of equations. Thus the problem reduces to the matrix equations for the expansion coefficients. The matrix elements are given in terms of the infinite integrals with a single variable and these may be transformed into infinite series that are convenient for numerical computation. The far field patterns of the scattered wave are computed and compared with those computed based on the physical optics approximation. The agreement between them is fairly good.


Jafri A.D.U.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University | Syed A.A.,Quaid-i-Azam University | Hongo K.,Nakashizu
Progress in Electromagnetics Research | Year: 2012

The scattering of an arbitrarily oriented dipole field by a circular disk with surface impedance is investigated by using the method of Kobayashi Potential (KP method). The dual integral equations (DIE) are produced during formulation of the problem. The solution of the DIEs is constructed in terms of set of functions which satisfy the boundary conditions as well as required edge conditions. At this stage, we applied the discontinuous properties of Weber Schafheitlins integral and vector Hankel transform. After applying the projection, the resulting expressions are reduced to the matrix equations for the expansion coeffcients. The matrix elements are given in terms of the infinite integrals. The far field patterns for the scattered wave are computed for di®erent incident angles, disk sizes and surface impedances for ρ-, φ- and z-directed dipole field excitation. To validate the results we have obtained the results based on the physical optics approximation and their comparison shows that they quite reasonably match.


Afzaal M.,Quaid-i-Azam University | Syed A.A.,Quaid-i-Azam University | Naqvi Q.A.,Quaid-i-Azam University | Hongo K.,Nakashizu
Optics Communications | Year: 2015

In this article, Kobayashi potential method has been used to investigate scattering from an impedance strip embedded in a homogeneous isotropic chiral medium. The discontinuous properties of the Weber-Schafheitlin's integral have been applied to incorporate the edge conditions. A set of matrix equations are obtained, using the projection properties of Jacobi's polynomials, and solved for unknown expansion coefficients of the fields. Monostatic and bistatic scattering widths have been determined for left and right handed Beltrami field excitations. Effects of variation in values of chirality, incident angle, impedance and width of strip on scattered fields have been investigated. The numerical results of the scattered fields for various parameters have been produced for comparison. © 2014 Elsevier B.V. All rights reserved.

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