Figure 1: Configuration of a typical four-element OAM-generating array.
From: Experimental Array for Generating Dual Circularly-Polarized Dual-Mode OAM Radio Beams
(a) Horizontally polarized, OAM mode 
 = +1. (b) Horizontally polarized, OAM mode 
 = −1. (c) The LHCP antenna array and its polarization decomposition. (d) The RHCP antenna array and its polarization decomposition.
