Effects of Interelement Spacing on the Input Impedance of Uniform Circular Arrays for Orbital Angular Momentum (OAM) Generation

Orbital angular momentum (OAM) has gained popularity as a multiplexing technique. However, little emphasis has been given to the network parameters of OAM generating antennas. In this paper, we calculate the input impedance of OAM-generating uniform circular arrays (UCA) of varying radius and monopole height using 4NEC2. For tightly coupled arrays, we observed that the elements’ input impedance varies significantly as a function of both monopole height and array radius. Our simulation results can be used for future designs that consider resonant, rather than electrically small, elements for improved gain and power efficiency.