The simplest description of a waveguide is really a kind of tube that directs electromagnetic waves from one end to another. They can be oldschool metallic microwave frequency waveguides or even optical fibers used for telecommunication. Electromagnetic waveguides specifically transmit waves from one point (input) to another (output) employing a material that is able to guide the waves. Waveguides are an integral part in most of our daily lives, if we are aware of it or not. Your microwave, radio, televisions, and most common electrical appliances have some of waveguides.
The basic behind waveguides is that they use total internal reflection of waves along a guiding structure. The waves bounce off the walls while moving forward, sort of being a pinball action. In a dielectric waveguide, like a coaxial cable that many cable boxes used up until recently, the wave moves through a solid bit of metal. This method does not bounce the wave around like a pinball, but rather conducts the wave through a metal wire. Coaxial cables usually employ copper as the conductive metal; a dielectric material covers the copper and allows the wave to continue to move through with minimal leakage.
Waveguides will also be an intrinsic section of satellite communications and radar. The signals are transferred through the waveguides to be able relay the signals to the various components of these systems. Radar systems found in avionics for aircraft specifically utilize waveguides to move signals between components.
Many waveguide are hollow, rigid, metal tubes that transfer the waves using the aforementioned pinball motion. There can be a substantial amount of applications for these kind of electromagnetic waveguides. In order to cut back the loss of the electrical signal, highly conductive materials coat the interior of the waveguides, such as copper, gold, or silver.
While many people might not know waveguides when they first hear the word, there are plenty of applications that the average person can understand. Not everyone may know how his or her microwave, radio, televisions, along with other electronics work, but waveguides play a crucial role inside the function of these electronics. Thankfully, you will find those who understand how you can utilize this technology and integrate it into our daily lives without us even being aware of it. I hope you enjoyed our little trip into the world of waveguides!
PS.: Just a quick update: As we have seen, waveguides are entities with a translational symmetry. From a theoretical point of view this can be used to simplify Maxwell’s equations and apply the so-called Boundary Element Method which may also be used to find the eigenmodes of the waveguides.