Generation of plane spiral orbital angular momentum microwave with ring dielectric resonator antenna

A ring dielectric resonator antenna is proposed to generate plane spiral orbital angular momentum (PSOAM) beam at 10 GHz. It consists of an isotropic and homogeneous ring dielectric and an outer cylindrical metal with a circular slot on its side surface. The simulated and experimental results show that this ring dielectric resonator antenna possesses the spiral phase characteristic of the OAM wave while propagates along the transverse direction with the main lobe around 90°. The PSOAM wave can avoid the on-axis phase singularities and amplitude nulls encounter by the traditional OAM beams. Compared with the reported PSOAM microwave antennas, this resonator antenna has more potential for mobile devices and short-range OAM wireless communication due to its small size.