Many people ask themselves this question upon hearing the term 'electromagnetic waveguide.' The most basic description of a waveguide is a sort of tube that directs electromagnetic waves from one end to another. Many times, these waves are microwave frequency when dealing with electromagnetic waveguide. There are also optical waveguides that direct a different spectrum of waves. The most common optical waveguide is fiber-optic cable, like the ones used for many modern television and internet companies.
Electromagnetic waveguides specifically transmit waves like radio and microwaves from point to point using a metal pipe or tube. Waveguides are actually an integral part of most peoples' daily lives, whether they are actively aware of this or not. Your microwave, radio, televisions, and most common electrical appliances have many waveguides. Waveguides are an integral part of most of the technology that everyone uses on a daily basis.
The basic principles behind waveguides are that they use metal to reflect the waves across a distance. The waves bounce off the walls while moving forward, sort of like a pinball action. In a dielectric waveguide, like a coaxial cable that most cable boxes used up until recently, the wave moves through a solid piece 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 are also an integral part of satellite communications and radar. The signals are transferred through the waveguides in order relay the signals to the various components of these systems. Radar systems used in avionics for aircrafts specifically utilize waveguides to move J-band signals between components. The J-band is a range of radio waves that range in the electromagnetic spectrum between 10 GHz to 20 GHz.
Many waveguide are hollow, rigid, metal tubes that transfer the waves using the aforementioned pinball motion. There is a substantial amount of applications for these types of electromagnetic waveguides. In order to reduce the loss of the electrical signal, highly conductive materials coat the inside of the waveguides, such as copper, gold, or silver.
While many people may not know what a waveguide is 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, and other electronics work, but waveguides play a crucial role in the function of these electronics. Thankfully, there are people who understand how to utilize this technology and integrate it into our daily lives without us even being aware.