Design Approaches for Identical Transmitter and Receivers for Long Distance OAM Communication

In this paper, we present an analytical solution for determining the uniform circular array transmitter radius in long-distance orbital angular momentum communication, ensuring identical receiver and transmitter radii for a given communication distance. Using the relation between beam divergence and the radius of the transmitter, we derive an equation to ensure identical radii for both the transmitter and receiver UCA. We simulate the generation of an OAM beam at 26 GHz for 50 m and 100 m distances using both modes 1 and 2. Further, we multiplex modes 1 and 2 in a concentric uniform circular array configuration and report the mode purity for a 50m distance.