A Circularly Polarized Multimode Patch Antenna for the Generation of Multiple Orbital Angular Momentum Modes

Vortex waves carrying orbital angular momentum (OAM) have received much attention due to their potential in communications and other aspects. In this letter, a multimode concentric circularly polarized patch antenna is designed to generate multiple OAM states. The proposed antenna is analyzed theoretically. Then, the simulated and measured electric fields are presented and verify that the proposed antenna is capable of generating multiple OAM states.