Spiral radio waves could transform broadcasting

Nature : To relieve congestion on radio bandwidths caused by the ever-growing number of smartphones and laptops, researchers at the Swedish Institute of Space Physics in Uppsala and the University of Padua in Italy are developing methods to create and detect spiral radio waves, which twist around a beam’s direction of propagation like fusilli pasta. Modulating the degree of twist provides an additional means to carry information and could potentially boost bandwidth by a factor of nine. To twist the beam, the researchers placed a spiral-staircase-like structure a few meters from an antenna. As the wavefront emitted from the antenna strikes the stepped reflector, it is broken into sections. Each subsequent section of the wave is delayed slightly from the one before it, resulting in different orbital angular momentum states. The group’s results appear in the New Journal of Physics.