Near-field Shaping by Leaky-Wave Metasurfaces: OAM and Bessel Beams Synthesis

We present and discuss the synthesis of Leaky-wave (LW) radiating metasurfaces for near-field applications. The metasurface sheet transition Impedance Boundary Condition (IBC) is computed after discretizing the relevant Electric Field Integral Equation (EFIE) with Fourier-Bessel basis functions. We have shown that the near-field of the MTS can be controlled with a very good accuracy, down to a height of about one wavelength from the surface. Several examples have been successfully designed, which cover Bessel beam radiators for focusing applications and multiple OAM beams. The designed MTSs are numerically validated with the Method of Moments (MoM).