AN IMPROVED DISCRETE COMPLEX IMAGE METHOD FOR GREEN'S FUNCTIONS IN MULTILAYERED MEDIA

摘要

The numerical implementation of traditional discrete complex image method (DCIM) approach for spatial-domain Green's functions (GFs) is limited to low values of ρ (ρ is the distance between the source and the field points of the GFs). Although recently a direct DCIM was introduced to obtain both near- and far-field region accurately, the direct DCIM was limited to choose the paths of k{sub}z plane in free-space layer. In this paper, an improved DCIM is introduced without any quasi-static and surface-wave extraction. We choose a novel path of k{sub}z plane. The improved DCIM works in both the near- and far-field region for multilayered media as direct DCIM does. And the method is applicable to choose the paths of k{sub}z plane in the layer where the source and field points are. The improvement makes it feasible to accelerate the calculation of spatial-domain GFs of electrically large buried objects in multilayered media. In this paper, the method developed for the computation of GFs is used for planar structures containing both lossless and lossy media. The CPU time used to perform the improved DCIM is less than 1 s for computing the fields, with a horizontal source-field separation from 1.6 × 10{sup}3λ{sub}0 to 16λ{sub}0 (λ{sub}0 is the free-space wavelength).