A waveguide is a structure that guides waves by restricting the transmission of energy to one direction.Waveguides are used to transmit high frequency signals with low attenuation and large bandwidth.
Waveguides are usually composed of thin metal wires or rods that form a periodic structure along the direction of propagation. They can also direct power precisely to where it is needed and function as a high-pass filter. Space waveguides can be used for applications such as transmitting signals between satellites, creating artificial plasma channels, and enhancing laser beams.
Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency waveguides which direct electromagnetic waves other than light like radio waves1.