Hard and soft surfaces realized by FSS printed on a grounded dielectric slab

Recently, a lot of research efforts have been devoted to periodic planar surfaces used to generate new equivalent boundary conditions. This work present new solutions for hard and soft surfaces realized by printing a "gangbuster type" frequency selective surface (FSS) on a grounded slab. Depending on the direction of wave propagation and on the nature - capacitive or inductive - of the printed FSS, these structures exhibit alternatively hard or soft properties.