Electromagnetic Wave Propagation

Abstract This article discusses the nature of electromagnetic wave propagation. After a brief historical overview and a description of the electromagnetic spectrum, plane waves are introduced as fundamental solutions to Maxwell's equations. Basic concepts such as wavelength, Poynting vector (power flux density), and phase velocity are explained in view of such waves. The transverse nature of electromagnetic waves and its relation to polarization is also discussed. The article continues with an examination of the relation between electromagnetic waves and sources, followed by a description of spherical and cylindrical waves. Next, the nature of electromagnetic wave propagation in lossy media is considered, where concepts such as frequency dispersion and group velocity are introduced. The interaction of electromagnetic waves with obstacles is treated next by considering scattering and diffraction phenomena, and, in more detail, the reflection and transmission (refraction) of electromagnetic waves across material boundaries. This is followed by a description of guided‐wave propagation, with emphasis on TE and TE modes in waveguides, and a description of surface and leaky waves. Finally, the article concludes by drawing the distinction between coherent and incoherent waves.