An asymptotic closed-form representation for the substrate-superstrate Green's function (microstrip antennas)

In order to overcome the limitations of previous methods (the spectral- and spatial-domain methods) for analyzing problems connected with the grounded double-layer (substrate-superstrate) configuration, the authors propose the use of an asymptotic closed-form representation of the spatial Green's function. This approach makes the mutual coupling computation extremely efficient and can be used even for relatively small lateral distances between source and observation points (usually down to a few tenths of the free-space wavelength). Numerical results are presented.<>