On the direct Green´s functions contribution for boxed microstrip geometries

This study reports a procedure for splitting up the Green´s functions for boxed microstrip geometries into the direct term, an homogeneous term and a remainder related to the interface reflections and diffraction at adjacent layers. The Green´s functions are faster and more accurately computed when used in solving integral equations or in generating fields since the direct singular term is given analytically, the homogeneous term is expressible in a suitable form and the remainder is expressed like a quite fast convergent series. The procedure is applicable to Green´s functions pertaining to any oriented or located source within the box.