Waveguide

A waveguide is used to direct a wave along a specific path. But waves emitted from a body falls off as it spreads out in all directions by the inverse of the area of the sphere intersecting the point originating at the source. So a wave needs amplification to keep flowing.

Aside from the amplifiers used in discrete points in telecommunications, the medium itself serves as an amplifier to counteract the attenuation of the fields

Types

• Acoustic Waveguides
  • Tin Can Telephone
• RF Waveguides
• Optical Waveguides
  • Optical Fibre
• Transmission Lines
  • Long lines need to take wave nature into account
  • In the past, the submarine telegraph cables faced interference, for which the theory of tranmission lines had to be devised.
  • In the present, submarine telecommunication cables are made of optical fibers, so the data is completely free of any interference.

Features

• Mode Profile
• Dispersion

We have to ask two questions about the waveguide to see how the signal will appear at the receiving end.

A waveguide can be treated as a Linear System, whose Transfer Function we have to find, alongside the "shape" of the wave within the waveguide -- for any arbitrary frequency -- to see if a given signal will arrive in phase or frequency at the receiving end.