Figure 3: Simulated (blue solid line) and measured (red solid line) far-field radiation patterns of three OAM modes at 18 [GHz].

(a,c,e) E-plane (ϕ = 90°) realized antenna gains of l = 0, l = +1, and l = −1 OAM modes, respectively. (b,d,f) H-plane (ϕ = 0°) realized antenna gains of l = 0, l = +1, and l = −1 OAM modes, respectively.