Analysis of terminated lossless planar multilayer periodic EBG Structures Using an equivalent CCITL model

Unsymmetrical planar multilayer periodic electromagnetic bandgap (EBG) structures, terminated in a surface impedance with an arbitrary number of dielectric layers in a unit cell, can be simplified by modelling these structures using equivalent periodic multi-section transmission lines (TL) terminated in a corresponding load impedance. These periodic multi-section TLs can be effectively analyzed using an equivalent model based on conjugately characteristic-impedance TLs (CCITLs). In this paper, both conjugate characteristic impedances with nonnegative characteristic resistances (NNCRs) and negative characteristic resistances (NCRs) are considered. It is found that the equivalent CCITL model yields accurate results and can simplify the analysis of these structures with more physical insight.