Multi-OAM-mode microwave communication with the partial arc sampling receiving scheme

An orbital angular momentum (OAM) multiplexed radio data link with the novel partial arc sampling receiving (PASR) scheme is experimentally demonstrated. These four coaxially propagating OAM waves with modes of l = -6, -2, +2 and +6 are generated by a Cassegrain antenna based on the dual ring-slot radiators. Over 10 m free-space transmission, four identical horn antennas uniformly located at the π/2 arc with a fixed radius of 45 cm are used to capture the four overlapped OAM waves. The de-multiplexing is then performed by digital phase-shift (DPS) at digital baseband. Experiment results show that the bit-error rates (BER) can reach below the forward error correction limit of 3.8 × 10^-3 for all the four OAM channels. Multi-OAM-mode communications with the PASR scheme is capable of providing the receiving end with desired properties of compact size as well as easy realization.