waveguide (rus. волновод) — natural or artificial channel that makes a wave of certain nature propagate along its axis or axial surface with relatively low attenuation, and limits such wave to the area close to the axis or axial surface.

Description

Wave localisisation within the propagation channel is achieved through reflecting from the waveguide walls or due to the focusing properties of the waveguide. Waveguides also include systems with surface waves guided along the interfaces.

By their origin, all waveguides are divided into two groups – natural waveguides and artificial waveguides.

Natural waveguides include, for example, ionospheric waveguides and underwater sound channels.

Artificial waveguides are used for energy or information (signal) transfer by various types of waves (acoustic and electromagnetic waves of different ranges).

A specific feature of waveguides is that they have (if the absorption is not very strong) a discrete set of guided modes (normal waves) that propagate without changing their structure.

Each guided mode is characterised by a limiting frequency that is called critical; a waveguide mode can exist only at frequencies above the critical. Some types of waveguides have modes with a critical frequency equal to zero.

Authors

  • Khokhlov Dmitry R.
  • Nanii Oleg E.

Source

  1. Physical Encyclopedic Dictionary (in Russian). — Moscow: Bol'shaja Rossijjskaja ehnciklopedija, 1995. — 928 pp.

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