An Adaptive Fitting Method for the Efficient Evaluation of Green's Functions in Planar Layered Media

An efficient and accurate fitting approach for computing spatial-domain Green's functions (SDGFs) in planar layered media is presented in this paper. The proposed approximation scheme uses two independent rational fitting models, and adaptively selects spatial-domain samples in each consecutive iteration. The iteration stops until the error between two rational models lower than the preset accuracy. Numerical results show the proposed method enables a robust and accuracy-controllable closed-form evaluation of the SDGFs for the electromagnetic field quantities with a minimized number of samples.