Editing Waveguide (section)

== Uses ==
[[File:Waveguide.aps.anl.gov.jpg|thumb|Waveguide supplying power for the [[Argonne National Laboratory]] [[Advanced Photon Source]].]]
The uses of waveguides for transmitting signals were known even before the term was coined. The phenomenon of sound waves guided through a taut wire have been known for a long time, as well as sound through a hollow pipe such as a [[cave]] or medical [[stethoscope]]. Other uses of waveguides are in transmitting power between the components of a system such as radio, radar or optical devices.  Waveguides are the fundamental principle of [[guided wave testing]] (GWT), one of the many methods of [[Nondestructive testing|non-destructive evaluation]].{{sfn|Olisa|Khan|Starr|2021}}

Specific examples:
* Optical fibers transmit light and signals for long distances with low attenuation and a wide usable range of wavelengths.
* In a [[microwave oven]] a waveguide transfers power from the [[magnetron]], where waves are formed, to the cooking chamber.
* In a radar, a waveguide transfers radio frequency energy to and from the antenna, where the [[Electrical impedance|impedance]] needs to be matched for efficient power transmission (see below).
* Rectangular and circular waveguides are commonly used to connect feeds of parabolic dishes to their electronics, either low-noise receivers or power amplifier/transmitters.
* Waveguides are used in scientific instruments to measure optical, acoustic and elastic properties of materials and objects. The waveguide can be put in contact with the specimen (as in a [[medical ultrasonography]]), in which case the waveguide ensures that the power of the testing wave is conserved, or the specimen may be put inside the waveguide (as in a dielectric constant measurement, so that smaller objects can be tested and the accuracy is better.{{sfn|Baker-Jarvis|1990}}
* A [[transmission line]] is a commonly used specific type of waveguide.{{sfn|EETech Media}}