Vector Vortex Wave Generation for Tunnel Communication

In this paper, we present a method to generate vector vortex wave that can carry Orbital Angular Momentum (OAM) and Spin Angular Momentum (SAM), for wireless communication in tunnels or similar structures. Inside a closed environment, vortex waves are free from beam divergence issue and show a central null in the field magnitude distribution. Additionally, these waves possess the ability to carry multiple modes at the same frequency due to the unique phase distribution on the phase front and greatly enhance the channel capacity. These distinctive characteristics make vortex waves favorable for wireless communication in tunnel like structures. In this work, we present a method to generate the vortex waves using a radial array of monopoles inside a metallic waveguide. Different shapes of metallic guided structures resembling typical tunnel forms used in transportation or mining are studied. Simulation results show that the proposed method can generate vortex waves inside such closed environments.