Electromagnetic Fields

Electromagnetic energy is transferred through propagation of waves. These waves can be described by their frequency, direction of propagation, and amplitude. When working with electromagnetic energy and physical devices, one of the fundamental concepts is that of “wavelength”. Wavelength is often expressed in metric units. The definition of wavelength is the speed of the propagation of energy divided by the frequency of that energy, expressed in Equation 5.1. Wavelength is determined by dividing the propagation velocity (in meters per second), by the frequency. Radio frequency energy propagates at about the speed of light, 186,000 miles per second or 300 million meters per second. The unit of frequency is Hertz (Hz.), formerly called “cycles per second” (cps). For example, if we want to determine the wavelength of a 100-MHz signal, the wavelength would be calculated from Equation 5.1 as 300/100 MHz or 3 meters.