Accession Number : ADA309065

Title :   Efficient Solution for Electromagnetic Scattering Using the Dual-Surface Magnetic-Field Integral Equation for Bodies of Revolution.

Descriptive Note : Rept. Sep 93-Mar 94,

Corporate Author : ROME LAB HANSCOM AFB MA

Personal Author(s) : Schmitz, James L.

PDF Url : ADA309065

Report Date : JUN 1995

Pagination or Media Count : 75

Abstract : The dual-surface magnetic-field integral equation (DMFIE) eliminates the spurious resonances from the magnetic-field integral equation (MFIE) for plane-wave scattering from bodies of revolution. The numerical predictions of scattering from a right circular cylinder were excellent using as little as seven segments per wavelength and simple pulse-basis and impulse-testing functions. The total solution time for electrically large bodies is reduced dramatically using the FFT and conjugate gradient (CG) method. The solution times using Gaussian elimination were proportional to (d/lambda)3 for axial incidence for a scatterer of equal width and length, d, and proportional to (d/lambda)4 at broadside incidence. For broadside incidence, matrix-fill time was reduced using the FFT to a (d/lambda)3log2(d/lambda) functional dependence, and CG reduced the solution time to (d/lambda)3. Therefore, the total CPU time for electrically large bodies of revolution is proportional to (d/lambda)3 for axial incidence and (d/lambda)3log2(d/lambda) for broadside incidence. The MFIE and the original DMFIE do not correctly produce the dominant current for scatterers with narrow tips, and these equations yielded incorrect results for bodies with these features. In coding the exact solution to scattering from the tip of an infinite cone into the computer program, the DMFIE was shown to calculate scattering from bodies with narrow tips accurately.

Descriptors :   *MAGNETIC FIELDS, *RADAR CROSS SECTIONS, *INTEGRAL EQUATIONS, MATHEMATICAL MODELS, ELECTRIC FIELDS, ELECTROMAGNETIC SCATTERING, BACKSCATTERING, FAR FIELD, MONOSTATIC RADAR, RESONANT FREQUENCY, SOLUTIONS(GENERAL), MATHEMATICAL PREDICTION, PARTIAL DIFFERENTIAL EQUATIONS, FAST FOURIER TRANSFORMS, ELECTRIC CURRENT, NUMERICAL METHODS AND PROCEDURES, PLANE WAVES, ELECTROSTATICS, ELECTRICAL MEASUREMENT, SPURIOUS EFFECTS, BISTATIC RADAR, BESSEL FUNCTIONS, BODIES OF REVOLUTION, MAGNETIC DIPOLES.

Subject Categories : Active & Passive Radar Detection & Equipment
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE