Encoding many channels on the same frequency through radio vorticity: first experimental test

We have shown experimentally, in a real-world setting, that it is possible to use two beams of incoherent radio waves, transmitted on the same frequency but encoded in two different orbital angular momentum states, to simultaneously transmit two independent radio channels. This novel radio technique allows the implementation of, in principle, an infinite number of channels in a given, fixed bandwidth, even without using polarization, multiport or dense coding techniques. This paves the way for innovative techniques in radio science and entirely new paradigms in radio communication protocols that might offer a solution to the problem of radio-band congestion. S Online supplementary data available from stacks.iop.org/NJP/14/033001/ mmedia 8 Author to whom any correspondence should be addressed. New Journal of Physics 14 (2012) 033001 1367-2630/12/033001+17$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft