Electromagnetic scattering by surfaces of arbitrary shape (original) (raw)
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IEEE journal on multiscale and multiphysics computational techniques, 2018
We present a non-conformal surface integral equation (SIE) method for the analysis of time-harmonic electromagnetic (EM) scattering by multiscale perfect electrically conducting (PEC) objects. To alleviate the burden of geometrical processing, a mixed triangle/quadrilateral mesh with arbitrary non-conformity is adopted in this method. A vectorial piecewise constant basis function is defined over the unstructured mesh as the trial and test function. The recently developed reverse operation self-consistent evaluation (ROSE) approach is employed to evaluate the hyper-singular integrals. Due to the utilization of this locally defined basis function, the function space is enlarged from the commonly used div-conforming space to the squareintegrable counterpart. Therefore, it will be possible to apply different polygonal elements or basis functions with different orders according to the local characteristics of the geometry. Several numerical results are presented to validate the accuracy and demonstrate the versatility of the proposed method for modeling multiscale and electrically-large PEC objects.
Numerical analysis of antenna by a surface patch modeling
IEEE Transactions on Magnetics, 1990
In this paper, the cylindrical dipole antenna is numerically analyzed by the moment method. Surface of the antenna is approximated by triangular patches and the electric field integral equation is used for direct calculation of the surface current distribution. Therefore we can treat the cylinder antenna in open or closed boundary form. The current expansion functions and the testing functions of the electric field boundary condition are triangular type. The surface integrals are numerically solved by a 33-point Gaussian quadrature approximation. The current distribution on a flat plate illuminated by a plane wave and the input admittance of a hollow cylindrical dipole as the near field quantities have been investigated. The convergence of the input admittance against the number of the triangular patches is presented and also the admittance solution is compared with the thin-wire approximation and theoretical results. Finally the CPU time and memory storage size for different number of patches are presented. Rapid admittance convergence and few required unknowns per square wavelength are the advantages of the surface patch modeling.
Progress In Electromagnetics Research, 2008
A new numerical method is proposed for the analysis of electromagnetic scattering from conducting surfaces. The method involves Monte Carlo integration technique in the Method of Moments solution of the Electric Field Integral Equation for determining the unknown induced current distribution on the surface of the scatterers. The unknown current distribution is represented in terms of a modified entire domain polynomial basis functions satisfying the appropriate edge conditions and symmetry conditions of the problem. This leads to very small order of the Method of Moments matrix as compared to the conventional sub-domain basis functions. The accuracy and the effectiveness of the method are demonstrated in three cases of scattering from conducting circular disks and results are compared with the solutions using conventional sub-domain basis functions. While the sub domain analysis is incapable of handling large domain problems, the proposed method overcomes this limitation. It is also observed that the proposed method is superior to conventional sub-domain method in dealing with singularity problem of the integral equation easily and efficiently.
Electromagnetic Scattering Analysis of SHDB Objects Using Surface Integral Equation Method
Photonics
A surface integral equation (SIE) method is applied in order to analyze electromagnetic scattering by bounded arbitrarily shaped three-dimensional objects with the SHDB boundary condition. SHDB is a generalization of SH (Soft-and-Hard) and DB boundary conditions (at the DB boundary, the normal components of the D and B flux densities vanish). The SHDB boundary condition is a general linear boundary condition that contains two scalar equations that involve both the tangential and normal components of the electromagnetic fields. The multiplication of these scalar equations with two orthogonal vectors transforms them into a vector form that can be combined with the tangential field integral equations. The resulting equations are discretized and converted to a matrix equation with standard method of moments (MoM). As an example of use of the method, we investigate scattering by an SHDB circular disk and demonstrate that the SHDB boundary allows for an efficient way to control the polari...
IEEE Antennas and Propagation Society International Symposium. Transmitting Waves of Progress to the Next Millennium. 2000 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.00CH37118), 2000
An original boundary integral equation approach is developed for an efficient and accurate electromagnetic analysis of arbitrarily-shaped three-dimensional conducting and dielectric structures, typically involved in scattering and antenna problems. A suitable analytical pre-processing on the field integral representation allows a straightforward implementation of the Nystrom method, which is based on a direct discretization of the surface integrals by means of two-dimensional quadrature formulas: this novel approach is alternative to the more common moment-method solutions and presents various attractive computational advantages. Numerical results have been derived for canonical 3D shapes to validate the proposed implementation.
Radio Science, 1990
Two forms of the so-called mixed-potential electric field integral equation (MPIE) are developed for two-dimensional, perfectly conducting (PC) surfaces of arbitrary shape in the presence of an infinite, PC wedge, subject to transverse electric excitation. One of the MPIEs is based on the Coulomb gauge while the other employs the Lorentz gauge. In either case the effect of the wedge is incorporated in the integral equation by means of the appropriate Green's functions, leaving the current distribution on the arbitrary surface as the only unknown. The Green' s functions are derived by the eigenfunction expansion technique. A well-established moment method procedure is adapted to numerically solve both forms of the MPIE. Computed results are presented for several cases of interest, and the relative merits of the Coulomb and Lorentz gauge MPIEs are discussed. ZHENG ET AL.: TRANSVERSE ELECTRIC WAVE SCATTERING
Singular Edge and Corner Basis Functions for Scattering from Conducting Plates
2018 48th European Microwave Conference (EuMC), 2018
The Method of Moments (MoM) is an efficient way of obtaining solutions of integral equations for 2D and 3D electromagnetic structures by subdividing them into simple shapes such as triangles and rectangles and using suitable polynomial basis functions to describe fields or currents. In the presence of sharp edges and corners, the currents may be unbounded and the accuracy of the solution may be poor due to the inappropriate model provided by a polynomial basis. Attempts to improve the accuracy by increasing the number of cells or the polynomial order of the basis functions may fail as a result. In this paper new basis functions are proposed with unbounded behavior, to more efficiently model edge and corner singularities for quadrilateral cells.
2011
In this paper, three dimensional electromagnetic scattering problem is solved by using pulse-sinc type basis functions in the Method of Moments (MoM) procedure. This method is applied to the scattering problems of a plane wave illuminated flat arbitrary geometries. Pulse-sinc based MoM formulation is developed, the current densities and radar cross section of different geometries are investigated. The radar cross section (RCS) for co-polarized and cross polarized cases of the flat plate geometries are compared with both of the results obtained from the sinc-sinc based formulation and SuperNEC. The results obtained by using pulse-sinc fornulation are in very good agreement with those of the SuperNEC.
A fast analysis of electromagnetic scattering by arbitrarily shaped homogeneous dielectric objects
Microwave and Optical Technology Letters, 2003
In this paper, we present a fast analysis of electromagnetic scattering by arbitrarily shaped 3D homogeneous dielectric objects. The solution is based on the PMCHW integral equation formulation. The method of moments (MoM) is used to solve the integral equations and the precorrected fast Fourier transform (P-FFT) method is used to eliminate the need to generate and store the square impedance matrix and to speed up the matrix–vector product. Several numerical examples are included, which illustrate the accuracy and capability of the present method. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 30–35, 2003