Abstract: A communications system, comprising: a surface wave channel for guiding electromagnetic surface waves; a transmitter, coupled to said surface wave channel for transmitting signals along said surface wave channel; one or more disrupters, arranged to be positioned at arbitrary locations on or adjacent said surface wave channel, and arranged to convert said surface wave signals to space wave signals; and one or more receiver terminals, arranged to be positioned at locations corresponding to said disrupters, each terminal comprising an antenna for receiving said space wave signals.

Abstract: A guiding medium for guiding radio frequency (RF) electromagnetic surface waves, comprising: a first surface, the first surface having an electrical impedance suitable for the propagation of electromagnetic surface waves; and a protection layer positioned on or adjacent the first surface.

Abstract: A surface wave launcher for launching electromagnetic surface waves, the launcher comprising: a waveguide having a feed end and a launch end; a feed structure coupled to the feed end of the waveguide; wherein the feed structure includes a first conductor; the waveguide comprises a first planar conductive layer having a feed end and a launch end, the feed end being coupled to the first conductor; and the waveguide is arranged to be positioned adjacent a surface suitable for guiding electromagnetic surface waves, wherein the width of the first planar conductive layer tapers from the launch end towards the feed end.

Abstract: A system for sensing disruption to a signal propagating along a guiding medium for guiding electromagnetic surface waves, the system comprising: a guiding medium for guiding electromagnetic surface waves; a transmitter arranged to transmit electromagnetic surface waves along the guiding medium; a receiver arranged to receive electromagnetic surface waves transmitted along the guiding medium and to measure changes to a signal transmitted via the guiding medium in order to sense disruption to said signals based on said measured changes.

Abstract: A system for detecting electromagnetic surface waves scattered from a guiding medium, the system comprising: a guiding medium for guiding electromagnetic surface waves; a transmitter arranged to cause electromagnetic surface waves to be transmitted along the guiding medium; at least one transducer arranged to receive electromagnetic waves scattered from said guiding medium as a result of disruption to a surface wave passing over the guiding medium; and a sensor coupled to the transducer and arranged to detect said received electromagnetic waves.