Multi-mode Circular Waveguide Antenna with Orbital Angular Momentum

Electromagnetic wave that carries orbital angular momentum (OAM) can be expected to have a large channel capacitance at the same frequency. In this paper, a circular waveguide antenna generating circular polarization (CP) and orthogonal two orbital angular momentum modes is presented. This antenna consists of two circular waveguides, an outer one and inner one, which generate OAM of orders l = ±1 modes and circular polarization of l = ±0, respectively. As the result, we have found the possibility of four independent transmission paths at 2.4 GHz.