An efficient numerical algorithm for solving scattering and inverse scattering problems of electromagnetic waves
Abstract
The development of an efficient numerical algorithm of determining the unknown material composition and shape of an arbitrary target from the measured electromagnetic waves in the far field region will enhance the capability of the defense radar system to defeat known evasive schemes. The first step in this research effort is the development of an efficient and versatile numerical algorithm for calculating the scattered electromagnetic waves/radar cross section by a target with known complex geometry and material property. Hence the purpose of this Phase 1 research is to develop an efficient numerical algorithm for solving two dimensional scattering problems. This is achieved by using a special finite difference method based upon a natural spatial discretization of the integral form of Maxwell's equations on a nonorthogonal gridsystem and the leapfrog finite differencing in the time domain. It has the advantages of being: (1) more efficient than other known numerical methods, (2) highly accurate due to the bodyfitted grid system, and (3) the easiest numerical method to implement boundary conditions. The capability and feasibility of this twodimensional computer code are tested by performing numerical simulations on few realistic examples, e.g., cylindrical objects with cross sections of metallic jet and a composite airfoil. In these processes, the radar cross sections as functions of both the incident angle and the scattering angle are calculated and they seem to be quite good.
 Publication:

Final Report
 Pub Date:
 September 1987
 Bibcode:
 1987ncc..rept.....C
 Keywords:

 Algorithms;
 Electromagnetic Scattering;
 Inverse Scattering;
 Scattering Cross Sections;
 Wave Scattering;
 Airfoils;
 Computer Programs;
 Electromagnetic Radiation;
 Finite Difference Theory;
 Maxwell Equation;
 Radar Cross Sections;
 Communications and Radar