3-DIMENSIONAL PLANAR RADIATING STRUCTURES IN STRATIFIED MEDIA

This article presents new developments concerning three-dimensional (3 -D) planar problems, that is, combinations of planar sheets of current oriented along normal and transverse directions in a stratified mediu m. The conducting structures are analyzed using an improved version of the mixed potential integral equation, including unknown currents alo ng three coordinate directions, and solved through a method of moments . The modifications needed in the integral equation to accommodate sim ultaneously normal and transverse currents are discussed. Detailed exp ressions for the Green's functions associated ,vith horizontal and ver tical dipoles are presented and cast as Sommerfeld integrals. A conven ient integration path is proposed for their estimation. Associated int erpolation problems are thoroughly discussed and symmetry and reciproc ity considerations are pointed out. Finally, two antennas have been bu ilt and studied to demonstrate the validity of the formulation: a shor t circuited microstrip antenna, and a two-layer patch antenna. (C) 199 7 John Wiley & Sons, Inc.