Radial Uniform Circular Antenna Array for Dual-Mode OAM Communication

A radial uniform circular array (UCA) is proposed for orbital angular momentum (OAM) generation and dual-mode communication based on a multilayer design. Theoretical derivation is presented for the demonstration of the OAM generation from radial UCAs. The UCA of single mode is realized by cascading an eight-dividing feeding network with equal magnitude and specific phases for each of two neighbor ports and eight microstrip antenna elements. Both the full-wave simulations and measurements of a final fabricated antenna array are carried out. From 5.72 to 5.95 GHz, the proposed antenna possesses good -15-dB bandwidths at the ±1 modes, and a very weak cross coupling (less than -24 dB) exists in this frequency band. The helical phase wavefronts are obtained, and the radiation patterns are presented. Moreover, the dual-mode multiplexing is achieved with isolations of different channels more than 19 dB in measurements.