Sadasiva M. Rao

Transient scattering by conducting surfaces of arbitrary shape

The time-domain electric field integral equation (EFIE) is used along with the method of moments to develop a simple and efficient numerical procedure for treating problems of transient scattering by arbitrary shaped conducting objects. The conducting surface is modeled by planar triangular patches for numerical purposes. Because the EFIE is used in the solution procedure, the method is applicable to both open and closed bodies. the EFIE approach is applied to the scattering problems of Gaussian plane wave illumination of a flat square plate and sphere. Comparisons of surface current densities and far-scattered fields are made with previous computations and good agreement is obtained in each case. >

A stable procedure to calculate the transient scattering by conducting surfaces of arbitrary shape

A solution procedure to obtain the transient scattering by arbitrarily shaped conducting objects directly in the time-domain using the marching-on-in-time method is presented. The late-time oscillations are eliminated by a simple stabilization procedure which involves a negligible amount of extra computation. Numerical results for surface current density and far-scattered fields are given for various structures and compared with other methods. >

Electromagnetic scattering from arbitrary shaped conducting bodies coated with lossy materials of arbitrary thickness

A simple and efficient numerical technique is presented to solve the electromagnetic scattering problem of coated conducting bodies of arbitrary shape. The surface equivalence principle is used to formulate the problem in terms of a set of coupled integral equations involving equivalent electric and magnetic surface currents which represent boundary fields. The conducting structures and the dielectric materials are modeled by planar triangular patches, and the method of moments is used to solve the integral equations. Numerical results for scattering cross sections are given for various structures and compared with other available data. These results are proved accurate by a number of representative examples. >

Analysis of transient scattering from composite arbitrarily shaped complex structures

A time-domain surface integral equation approach based on the electric field formulation is utilized to calculate the transient scattering from both conducting and dielectric bodies consisting of arbitrarily shaped complex structures. The solution method is based on the method of moments (MoM) and involves the modeling of an arbitrarily shaped structure in conjunction with the triangular patch basis functions. An implicit method is described to solve the coupled integral equations derived utilizing the equivalence principle directly in the time domain. The usual late-time instabilities associated with the time-domain integral equations are avoided by using an implicit scheme. Detailed mathematical steps are included along with representative numerical results.

Electromagnetic radiation and scattering from finite conducting and dielectric structures: surface/surface formulation

An efficient and accurate numerical procedure for the analysis of the electromagnetic scattering and radiation from arbitrarily shaped, composite finite conducting and dielectric bodies is proposed. A set of coupled electric field integral equations involving surface equivalent electric and magnetic currents is used. The coupled integral equations are solved through planar triangular patch modeling and the method of moments. Two separate, mutually orthogonal vector functions for each edge connecting a pair of triangular patches have been developed. Numerical results for disk/cone and cylinder/cone structures are compared with other available data. Limited comparison with experimental data has also been made. >

An alternative version of the time-domain electric field integral equation for arbitrarily shaped conductors

An alternative version of the time-domain electric field integral equation for arbitrarily shaped conducting structures is presented. The advantage of the present approach is that the electric field integral equation has one less derivative with respect to time than the popularly used one. Hence, with this approach one does not need to differentiate the excitation. Therefore impulse and step function excitations of the conducting structures are possible in addition to the conventionally used Gaussian excitations. This alternative version is also quite accurate compared with a frequency-domain solution. >

Numerical solution of time domain integral equations for arbitrarily shaped conductor/dielectric composite bodies

In this work, we present a numerical solution of the coupled time domain integral equations to obtain induced currents and scattered far fields on a three-dimensional, arbitrary shaped conducting/dielectric composite body illuminated by a Gaussian electromagnetic plane wave pulse. The coupled integral equations are derived utilizing the equivalence principle. The solution method is based on the method of moments and involves the triangular patch modeling of the composite body, in conjunction with the patch basis functions. Detailed mathematical steps along with several numerical results are presented to illustrate the efficacy of this approach.

An efficient method to evaluate the time-domain scattering from arbitrarily shaped conducting bodies

In this work, we present a new and efficient numerical method to calculate the electromagnetic scattering from arbitrarily shaped conducting bodies directly in the time domain. The solution method is based on the method of moments, and involves the triangular patch modeling of the arbitrary body in conjunction with the patch basis functions. Detailed mathematical steps along with several numerical results are presented to illustrate the efficacy of this approach.xa0© 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 321–325, 1998.

Transient analysis of electromagnetic scattering from wire structures utilizing an implicit time‐domain integral‐equation technique

An implicit version of the time-domain integral equation is presented for the analysis of electromagnetic scattering from wire structures. The advantage of the implicit form is that for large values of the time step, the method is unconditionally stable over the explicit version. Numerical results are presented to illustrate the efficacy of this approach.xa0© 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 66–69, 1998.

Transient scattering from dielectric cylinders - E-field, H-field, and combined field solutions

In this work, the problem of transient scattering by arbitrarily shaped two-dimensional dielectric cylinders is solved using the marching-on-in-time technique. The dielectric problem is approached via the equivalence principle. Three different formulations, namely, the electric field integral equation formulation, the magnetic field integral equation formulation, and the combined field integral equation formulation are considered. Numerical results are presented for two cross sections, namely, a circle and a square, and compared with inverse discrete Fourier transform (IDFT) techniques. In each case, good agreement is obtained with the IDFT solution.