Scattering from 3-D multi-layered surfaces using adaptive integral method

Like the fast multipole method (FMM), the adaptive integral method (AlM) is a fast integral method that has O(N/sup /spl alpha//logN), /spl alpha/<1.5 computational complexity and O(N/sup /spl alpha//), /spl alpha/<1.5 memory requirements. AlM achieves its memory and complexity reduction by mapping the original edge-basis functions onto a regular grid and then using the Toeplitz property of the Green´s function along with the fast Fourier transform (FFT) for a fast execution of the matrix-vector products in the iterative solver. So far, application of AIM has been restricted to metallic structures. In this paper, we extend AIM to modeling scattering by three dimensional multi-layered surfaces. For validation RCS results are given for layered and coated spheres and for composite wing-like structures.