Radiation from vertical dipoles in the presence of homogenized omnidirectional metasurfaces

Radiation from vertical dipole sources placed inside a grounded dielectric slab covered with a thin microstructured metal screen having annular geometry is studied. The screen is represented through a locally homogenized surface impedance dyadic independent of the azimuthal coordinate, hence is a homogenized omnidirectional metasurface. The excited field is also omnidirectional; we propose here both analytical and numerical models for the calculation of its far-field pattern, the former valid for radially constant surface impedances, the latter valid for piecewise-constant impedances.