Modelling EBG surfaces using amended DB boundary conditions

Paper i proceeding, 2011

Recently the so-called DB boundary conditions were introduced that exhibit characteristics similar to that of an isotropic soft surface, except for an anomaly at normal incidence. This anomaly has also been amended, and the amended DB boundary condition has been shown to represent reflection from an EBG surface within the bandgap. The present paper summarizes the calculated characteristics of a practical planar EBG surface when modelled both with CST and the homogenous PMC-amended DB boundary condition. The paper also shows that the surface of an anistrotropic material with zero eps_z and mu_z will behave similar to the original DB boundary condition, and this is used to understand the anomaly for normal incidence by studying the case of eps_z and mu_z approaching zero.