The transition between bound and surface-leaky modes on one-dimensional periodic printed structures

In this work, the transition between bound and leaky modes on one-dimensional periodic structures printed on a grounded dielectric substrate is examined for the first time. Such structures support leakage into surface waves as well as into space due to the presence of the substrate. The solutions in this transition region are calculated using an accurate full-wave spectral-domain moment-method solution that allows for the determination of both physical and nonphysical solutions, both of which play an important role in the transition region.