A closed-form spatial Green's function for finite dielectric structures

A novel technique to derive the closed-form spatial Green's function for finite dielectric structures is presented by employing a combination of the characteristic Green's function (CGF) and complex images (CI) techniques. To show the versatility of this technique, a two-dimensional finite dielectric substrate is studied in detail. Since the structure is nonseparable, the derived Green's function is an approximate solution especially in the corners. It is shown that by applying certain corrections on the reflection coefficient of the fields at edges, more accurate results are obtained. The derived Green's function exhibits excellent agreement with the available rigorous method of moments solution of the problem.