Efficient use of closed form Green´s functions for the electromagnetic scattering by 3D buried objects

We present compact and efficient closed form expressions for the mixed potential Green´s functions in multilayered media with general electric and magnetic sources. By generalizing the Sommerfeld identity we can express also the first and second order Sommerfeld integrals in closed form and the spatial domain Green´s functions can be obtained in closed form without numerical differentiation. The presented formulation leads to a very efficient method since in each layer the GPOF approximations are needed only for three (source layer) or four (other layers) spectral domain Green´s functions. The applied mixed potential integral equations, identical with the Michalski-Zheng (1990) C-formulation (MZC), are solved by the method of moments (Galerkin´s method) with the Rao-Wilton-Glisson (RWG) basis functions. The developed method has been applied for the analysis of complicated 3D microstrip structures and scattering by various 3D objects.