MULTIWAVELENGTH 3-DIMENSIONAL SCATTERING WITH DUAL-SURFACE INTEGRAL-EQUATIONS

We apply dual-surface integral equations, which have the same form as, and yet eliminate, the spurious solutions from conventional electric- and magnetic-field integral equations, to determine the scattering from multiwavelength, three-dimensional perfect conductors. We determine accuracy by increasing the patch density and by comparisons with a high-frequency solution, a finite-difference time-domain solution, and measurements. Surface currents and scattered far fields computed with the dual-surface magnetic-field equation are displayed for perfectly conducting cubes 3 and 15 wavelengths on a side. Condition numbers and the number of iterations for convergence of the conjugate gradient method are shown to be linearly related to the electrical size of the scatterer. The logarithmic relationship between the number of iterations and the inverse of the residual error is also confirmed. For large scatterers the number of computer operations increases as the fifth power of electrical size; however, on massively parallel computers the run time increases only as the third power of the electrical size.