Figure 4: Fabricated prototype of the antenna array.
From: Experimental Array for Generating Dual Circularly-Polarized Dual-Mode OAM Radio Beams

(a) Front view. (b) Back view. (c) The near-field test scenario in the anechoic chamber.
From: Experimental Array for Generating Dual Circularly-Polarized Dual-Mode OAM Radio Beams
(a) Front view. (b) Back view. (c) The near-field test scenario in the anechoic chamber.