Systems and methods for focusing beams with mode division multiplexing

A system for focusing an orbital angular momentum (OAM) multiplexed beam, comprising:

• OAM signal processing circuitry for generating an OAM multiplexed signal, the OAM multiplexed signal including a plurality of data streams each having a unique orbital angular momentum applied thereto and multiplexed together within the OAM multiplexed signal, each of the unique orbital angular momentum comprising a beam helicity value greater than l=2;
• a plurality of antennas comprising an antenna array;
• an antenna array control circuit for controlling transmission of the multiplexed OAM signal from each of the plurality of antennas in the antenna array toward a focus point located below ground as a transmission beam to cause a transmitted plurality of OAM multiplexed signals to converge at the focus point below the ground at substantially a same time to overcome a divergence of the transmitted plurality of OAM multiplexed signals caused by the beam helicity value of greater than l=2 for each of the unique orbital angular momentum.

A controller for an antenna array, comprising:

• an interface for interconnecting the controller with the antenna array comprising a plurality of transmitting antennas;
• and
• a processor for generating control signals for controlling transmissions of an orbital angular momentum multiplexed signal from the antenna array, the OAM multiplexed signal including a plurality of data streams each having a unique orbital angular momentum applied thereto and multiplexed together within the OAM multiplexed signal, each of the unique orbital angular momentum having a beam helicity value greater than l=2, the processor configured to generate control signals to cause the antenna array to transmit the OAM multiplexed signal from each of the plurality of transmitting antennas of the antenna array toward a focus point located below ground as a transmission beam and control a timing of the transmissions of the OAM multiplexed signal from each of the plurality of transmitting antennas of the antenna array to cause a transmitted plurality of OAM multiplexed signal from each of the plurality of transmitting antennas to converge at the focus point below the ground at substantially a same time to overcome a divergence of the transmitted plurality of OAM multiplexed signals caused by the beam helicity value of greater than l=2 for each of the unique orbital angular momentum.