On the use of the duality principle for the determination of electric and magnetic Green´s functions for nonhomogeneous structures

Using the magnetic and electric potential vectors approach, the Green´s functions for general discontinuities and antenna problems are developed. It is proved that either the magnetic or the electric Green´s function for a nonhomogeneous (stratified) structure can be obtained from the complete eigenfunction spectrum of the structure using both the duality principle and the orthogonality property of the eigenfunctions. Consequently, a general stratified structure including conductor strips and/or slots can be analyzed using the same set of the Green´s functions. This analysis shows the validity of the duality principle in the case of nonhomogeneous structures and its promising potential applications for general structure configurations. The analysis is presented for coaxial fed and coplanar fed microstrip patch antennas, and it is proved that they can be studied using the same set of Green´s functions.<>