Showing papers by "Qaisar Abbas Naqvi published in 2009"
TL;DR: In this article, a cylindrical reflector is placed in a homogeneous, reciprocal and isotropic chiral medium and the high frequency fields of the reflector are analyzed.
Abstract: High frequency fields of a cylindrical reflector are analyzed. Cylindrical reflector is placed in a homogeneous, reciprocal and isotropic chiral medium. It is assumed that chiral medium simultaneously supports modes with negative and positive phase velocity. Present work is an extension of a previous work.
37 citations
TL;DR: In this paper, a line source from a perfect electromagnetic conductor (PEMC) circular cylinder coated with double positive (DPS) material or double negative (DNG) material is investigated theoretically.
Abstract: Electromagnetic scattering of a line source from a perfect electromagnetic conductor (PEMC) circular cylinder coated with double positive (DPS) material or double negative (DNG) material is investigated theoretically. The response of the coated PEMC circular cylinder is observed and it is noted that how the results obtained for this configuration differ from those of a coated perfect electric conductor (PEC) circular cylinder. It is assumed that both the PEMC cylinder and the coating layer are infinite along the cylinder axis. The comparison of directivity of coated PEMC cylinder and coated PEC cylinder is presented.
30 citations
TL;DR: In this paper, the authors used the Maslov's method to derive the expressions for high frequency flelds around the focal region of a paraboloidal re∞ector coated with isotropic and homogeneous chiral medium.
Abstract: Maslov's method is used to derive the expressions for high frequency flelds around the focal region of a paraboloidal re∞ector coated with isotropic and homogeneous chiral medium. The fleld expressions thus calculated are solved numerically, and the results are presented in the paper. Moreover, the dependency of the electric fleld on the thickness of the coated chiral medium and its properties is also studied. The results of this study are presented in the paper, and the conclusions are drawn accordingly.
28 citations
TL;DR: An analytical solution for the scattering of electromagnetic plane waves from an infinitely long nihility cylinder, coated with a double positive (DPS), double negative (DNG), epsilon negative (ENG), or mu negative (MNG) layer of uniform thickness is presented in this article.
Abstract: An analytical solution for the scattering of electromagnetic plane waves from an infinitely long nihility cylinder, coated with a double positive (DPS), double negative (DNG), epsilon negative (ENG), or mu negative (MNG) layer of uniform thickness is presented. The solution is determined by solving the scalar wave equation in the cylindrical coordinates, for different regions and applying the appropriate boundary conditions at the interfaces. Both TM and TE polarizations as incident plane have been considered in the analysis. Comparison of behaviors of a coated nihility cylinder with a coated PEC cylinder has been made. It is noted that two situations are more closer for DNG coating as compared to DPS coating.
28 citations
TL;DR: In this article, a perfect electric conductor placed in chiral nihility medium and excited by a uniform plane wave has been considered as an original problem using fractional operators, solutions to Maxwell equations which may be regarded as intermediate step between the original solution and dual to the original solutions are determined.
Abstract: A perfect electric conductor placed in chiral nihility medium and excited by a uniform plane wave has been considered as an original problem. Using fractional operators, solutions to Maxwell equations which may be regarded as intermediate step between the original solution and dual to the original solution are determined. Each fractional operator is composed of fractional curl operator. As more than one dual to original solution exists, so in each case, corresponding impedance of the fractional dual reflector has been determined.
27 citations
TL;DR: In this paper, the authors derived high frequency field expressions for a cylindrical reflector, which is composed of a chiral nihility layer backed by perfect electromagnetic conductor (PEMC), based on Maslov's method.
Abstract: High frequency field expressions for a cylindrical reflector, which is composed of a chiral nihility layer backed by perfect electromagnetic conductor (PEMC), have been derived. The treatment is based on Maslov's method. Dependence of co-polarized and cross-polarized field components for different values of admittance parameter of PEMC has been studied.
27 citations
TL;DR: In this article, the authors used fractional curl operators to find the dual solutions to the original solution of the Maxwell equations for chiral nihility medium, which may be regarded as intermediate step between the original and dual solutions.
27 citations
TL;DR: In this article, three fractional dual solutions between the original and dual to original solutions are determined inside the chiral nihility slab and corresponding fields outside the nihile slab are determined and analyzed.
Abstract: Inside the chiral nihility slab, three fractional dual solutions between the original and dual to original solutions are determined. Chiral nihility slab is backed by perfect electric conductor. Corresponding fields outside the nihility slab are determined and analyzed. It is noted that in only one case outside field is also fractional dual while for other two cases corresponding fields are not fractional dual.
23 citations
TL;DR: In this article, high frequency Fleld expressions are derived at the focal points of a paraboloidal re∞ector placed in a homogenous and reciprocal chiral medium, and some numerical results including contour plots and line plots are obtained using the derived expressions.
Abstract: High frequency fleld expressions are derived at the focal points of a paraboloidal re∞ector placed in a homogenous and reciprocal chiral medium. Firstly Geometrical Optics (GO) fleld expressions are derived for the paraboloidal re∞ector placed in chiral medium. As the GO fails at the focal points, so Maslov's method has been used to flnd the fleld expressions which are also valid around the focal point. By using hybrid space, Maslov's method combine the simplicity of ray theory and the generality of Fourier Transform method. Some numerical results including contour plots and line plots around the focal region of paraboloidal re∞ector placed in chiral medium are obtained using the derived expressions.
21 citations
TL;DR: In this paper, the authors investigated the response of a line source scattered by a nihility cylinder, coated with a double positive (DPS) or double negative (DNG) layer, and observed that the results obtained for this configuration differ from those of a coated perfect electric conductor (PEC) cylinder.
Abstract: Electromagnetic radiation of a line source scattered by a nihility cylinder, coated with a double positive (DPS) or double negative (DNG) layer, is investigated theoretically. The response of coated nihility circular cylinder is observed and it is noted that how the results obtained for this configuration differ from those of a coated perfect electric conductor (PEC) cylinder. It is assumed that both the nihility cylinder and the coating layer are infinite along the cylinder axis. The obtained numerical results are compared with the published literature. It is seen by the analysis that the directivity of the coated cylinder may be further increased when the PEC cylinder is replaced by a nihility cylinder as a core of the coated geometry at an optimized frequency.
20 citations
TL;DR: In this article, an infinitely long conducting strip which is placed on a dielectric slab of finite thickness is formulated rigorously, and the method of analysis is Kobayashi potential.
TL;DR: In this article, the authors studied the difiraction from a slit in perfectly electromagnetic conducting (PEMC) plane and the method of analysis is Kobayashi potential (KP).
Abstract: In the present investigation, difiraction from a slit in perfectly electromagnetic conducting (PEMC) plane has been studied. Both the E- and H-polarization are considered and the method of analysis is Kobayashi Potential (KP). The mathematical formulation involves dual integral equations (DIEs). These DIEs are solved by using the discontinuous properties of Weber-Schafheitlin's integral. The resulting expressions, flnally, reduce to matrix equations. These are then used to compute the values of unknown expansion coe-cients. Numerical results are presented for difierent parameters of interest especially the dependance of co-polarized and cross-polarized components on the admittance parameter.
TL;DR: In this paper, the behavior of a fractional rectangular impedance waveguide with respect to the original impedance of walls of the guide as well as fractional parameter has been studied using fractional curl operator.
Abstract: Fractional rectangular impedance waveguide has been studied using fractional curl operator. Behavior of fleld inside the fractional rectangular impedance waveguide has been studied with respect to the original impedance of walls of the guide as well as fractional parameter. Analysis of the impedance of the walls as well as power distribution over the cross sectional plane of fractional impedance rectangular waveguide has been given. It has been found that fractional curl can be used to control the power distribution pattern over the cross sectional plane.
TL;DR: In this paper, the defect in high frequency solution due to geometrical optics is overcomed by Maslov's method and numerical computations are made for the field pattern around the caustic.
Abstract: In this paper, Maslov's method has been used to obtain the high frequency field refracted by a hyperboloidal focusing lens. High frequency problem which contains caustic region is transformed into caustic free problem by transforming the situation into mixed domain. The high-frequency solution that includes the caustic region is obtained from geometrical optics. The defect in high frequency solution due to geometrical optics is overcomed by Maslov's method. Numerical computations are made for the field pattern around the caustic. The results are found in good agreement withobtained using Debye-Wolf focusing integral.
TL;DR: In this paper, an infinite and a finite length PEMC circular cylinder, illuminated by an arbitrarily oriented dipole, is investigated theoretically, and an electric dipole as a source of excitation is considered first, and then a magnetic dipole is treated.
Abstract: Electromagnetic scattering from an infinite and a finite length PEMC circular cylinder, illuminated by an arbitrarily oriented dipole, is investigated theoretically. An electric dipole as a source of excitation is considered first, and then a magnetic dipole as a source of excitation is treated. In contrast to the case of an axially directed dipole, it is shown that no additional terms are needed to incorporate the cross-polarized component of the field for the case of radial and circumferential dipoles. Numerical verifications are presented to verify the validity of derived results and numerical code by comparing results with the published literature.
TL;DR: In this article, the authors analyzed focal region flelds of a PEMC paraboloidal re∞ector placed in homogenous and reciprocal chiral medium under the efiect of high chirality parameter.
Abstract: Focal region flelds of a perfect electromagnetic conductor (PEMC) paraboloidal re∞ector placed in homogenous and reciprocal chiral medium are analyzed under the efiect of high chirality parameter. The chiral medium supports both negative phase velocity (NPV) and positive phase velocity (PPV) modes simultaneously under strong electromagnetic coupling. The geometrical optics (GO) flelds have singularities at the focal region. Therefore, to avoid these singularities Maslov's method is used for the focal region flelds. The results obtained using this method are solved numerically, and line plots for the re∞ected fleld of the paraboloidal PEMC re∞ector are obtained for difierent values of admittance of the PEMC paraboloidal re∞ector and chirality parameter of the medium.
TL;DR: In this paper, a paraboloidal PEMC re∞ector placed in homogenous and reciprocal chiral medium is analyzed and the results obtained by this method are solved numerically.
Abstract: Focal region flelds of perfect electromagnetic conductor (PEMC) paraboloidal re∞ector placed in homogenous and reciprocal chiral medium are analyzed. Maslov's method is used to derive the expressions for the focal region flelds because the geometrical optics (GO) fails at these points. The results obtained by this method are solved numerically, and line plots for the re∞ected fleld of the paraboloidal PEMC re∞ector are obtained for difierent values of admittance of the PEMC re∞ector and chirality parameter of the medium.
Journal Article•
TL;DR: An analytical solution for the scattering of electromagnetic plane waves from an infinitely long nihility cylinder, coated with a double positive (DPS), double negative (DNG), epsilon negative (ENG), or mu negative (MNG) layer of uniform thickness is presented in this paper.
Abstract: An analytical solution for the scattering of electromagnetic plane waves from an infinitely long nihility cylinder, coated with a double positive (DPS), double negative (DNG), epsilon negative (ENG), or mu negative (MNG) layer of uniform thickness is presented. The solution is determined by solving the scalar wave equation in the cylindrical coordinates, for different regions and applying the appropriate boundary conditions at the interfaces. Both TM and TE polarizations as incident plane have been considered in the analysis. Comparison of behaviors of a coated nihility cylinder with a coated PEC cylinder has been made. It is noted that two situations are more closer for DNG coating as compared to DPS coating.
TL;DR: In this paper, high frequency fields, refracted by a geometry containing a Wood lens placed at a certain distance from a planar uniaxial interface, are derived by using Maslov's method.
Abstract: High frequency fields, refracted by a geometry containing a Wood lens placed at a certain distance from a planar uniaxial interface, are derived by using Maslov’s method. The geometrical optics approximation generally valid for high frequency fields fails in the vicinity of a caustic. Maslov’s method is a systematic procedure for predicting the field in the caustic region, combining the simplicity of the ray and the generality of the transform method. Numerical computations are made for the field pattern around the caustic by using Maslov’s method. The results are found to be in good agreement with those obtained using Kirchhoff’s approximation.