An experimental system for generating and identifying tunable orbital angular momentum in radio

An experimental system for communication using orbital angular momentum (OAM) is described in this paper. Both the transmitter and the receiver of the system have 9 independent ports, one of which is to provide a reference phase. By dynamically configuring the feeding signals of the uniform circular array (UCA) through these independent ports, the system is able to generate different OAM states in radio. The reception of the OAM modes, which is seldom discussed in previous published literature, is also analyzed. Different OAM states can be identified without changing the physical layout of the platform. The experimental results verify the feasibility of the platform for generating and identifying different OAM modes, laying a foundation for further research on multiplex transmission using OAM.