Calculation Of Green's Functions In Planar Stratified Structures And It's Applications For Analysis Of Microstrip Structures

Planar stratified structure is widely used in geophysical detecting, environment in-specting, microstrip antennas and circuits, and so on. With the fast developing of com-puter technology, how to analyze its EM characteristics more strictly and quickly is be-coming a hot topic in recent years.In this paper, spectral domain method is adopted to derive the Green's functions in arbitrary planar structures, which arise in the C class Mixed Potential Integral Equation (MPIE) that has a better singularity. The spatial Moment method (MoM) based on RWG basal function is employed to solve integral equation. Then, these methods are implemented to analyze the scattering properties of multiplayer microstrip antennas andmicrostrip circuits. After the deriving of spectral Green's functions in arbitrary stratified structures which based on transmission line theory is introduced, spatial Green's functions are calculated by implementing the two levels Discrete Complex Image Method. As the key point in this paper, an accurate approach for extracting the surface wave is discussed in detail. In order to locate the surface wave poles fast and accurately, a two-level search procedure by using the Newton-Raphson method is involved, and this method is proved out by referring to published results. A robust contour integration method is employed to calculate the residuals at each pole accurately so that the complicated analytical cal-culating for residuals is avoidable. Numerical results for the Green's functions of one-layer and two-layer structures are presented to verify the accuracy and efficiency of this approach by comparing with published papers. Moreover, there are several prob-lems like the Right Vector V should be treated in particular when MoM is applied in stratified structures, and they also have been simply discussed. In the end, several ex-amples are presented to verify the validity of all these approaches, which including the scattering from microstrip structures and kinds of microstrip circuits, and the results are in good agreement with the simulation results of commercial software.