Helical Array for the Generation of OAM Wave Without Phased Network

This letter proposes a helical array of eight rectangular patch elements to generate various orbital angular momentum (OAM) modes by adjusting successive distances between elements. The proposed helical array eliminates the need for various power-dividing phased feeding networks, which are required for generating different OAM modes. Both the simulation and the measurement results show that the proposed helical array can produce the topological charge of
± l
using a single feed network. The simulation and measurement of 8-element helical array for OAM mode ±1, +2, +3 are presented. The designed structure offers the flexibility to switch between OAM modes by varying the distance between antennas. A comparison of the helical array with the conventional uniform circular array is also tabulated.