Accession Number : ADA198098

Title :   Numerical Methods to Solve the Problem of Scattering from Electrically Large Bodies.

Descriptive Note : Technical rept.,

Corporate Author : ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB

Personal Author(s) : Chang, A ; Mittra, R

PDF Url : ADA198098

Report Date : Aug 1988

Pagination or Media Count : 59

Abstract : An alternative to directly inverting the large MoM matrix is to recast the problem in a form that is suitable for solution via iterative schemes. Although the use of iterative methods may enable one to treat scatterers that are an order of magnitude larger electrically, a close examination of them shows that most of them are not well-suited for handling multiple excitations in an efficient manner. In this report some variational-iteration schemes based on the use of prechosen entire domain basis functions that are suitable not only for treating larger bodies but for handling multiple incident angles as well are suggested. It is shown that, for this type of variational iteration schemes, the choice of an initial guess plays an important role in achieving a rapid convergence. Also, in an effort to further improve the convergence, a hybrid technique, where the method of moments is utilized to generate better gradient vectors in the iterative procedure, is developed. A simple case of scattering from a perfectly conducting or resistively-loaded strip is use to demonstrate the effectiveness of the methods. Keywords: Electromagnetic scattering, Iterative methods, Radar cross sections, and Resistive strips. (KR)

Descriptors :   *ELECTROMAGNETIC SCATTERING, *ITERATIONS, *NUMERICAL METHODS AND PROCEDURES, *RADAR CROSS SECTIONS, CONVERGENCE, ELECTRICAL PROPERTIES, HYBRID SYSTEMS, LOADING(ELECTRONICS), MOMENTS, RESISTANCE, SCATTERING, PROBLEM SOLVING

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE