Tripling the capacity of a point-to-point radio link by using electromagnetic vortices

Abstract

In this paper we report the results from outdoor experiments showing that it is possible to increase the data transmission capacity using at least three coherent, orthogonal beams on the same frequency, 17.128 GHz, each in a unique orbital angular momentum state. Each beam was encoded with the digital modulations used in present-day telecommunications. We achieved an error-free throughput of 3 × 11 Mbit/s with four-Quadrature Amplitude Modulation over a 7 MHz bandwidth over 100 m and 150 m long links.