Device that constrains the path of electromagnetic wave s (see electromagnetic radiation ).
It can be used to transmit power or signals in the form of waves while minimizing power loss. Common examples are metallic tubes, coaxial cable s, and optical fibres (see fibre optics ). Waveguides transmit energy by propagating transmitted electromagnetic waves through the inside of a tube to a receiver at the other end. Metal waveguides are used in such technologies as microwave oven s, radar systems, radio relay systems, and radio telescope s.