Fourier propagated (a) magnitude and (b) phase, at a distance of z = 100λ, generated by the simplified fields of Figures 6c and 6d. Fourier propagated (c) magnitude and (d) phase, at a distance of z = 100λ, for the HyG wave of order m = +1. The four stronger regions in (a) and (c) are due to the square shape of the aperture formed by the metasurface (size 5λ × 5λ). Using a circular metasurface would result in a better approximation of the ideal doughnut shaped magnitude of Figure 6a.