Electromagnetic theory and wave propagation

Abstract

The Maxwell equations lay the foundation of all classical electromagnetic phenomena. They describe how time-varying electric fields give rise to magnetic fields and vice versa. At boundary of two different media the permittivity, permeability, and conductivity can change sharply. Boundary conditions are discontinuity equations to specify corresponding discontinuity in the field vectors. Scalar and vector potentials are useful auxiliary functions in analysis of an electromagnetic field, under Lorenz gauge condition the decoupled equations of the potentials identically satisfy the Maxwell equations. Green’s function is an important tool in obtaining the solution for general source distributions. Poynting’s theorem is a law of conservation of energy for the electromagnetic field. Plane waves are the simplest and fundamental electromagnetic waves. In remote sensing applications, electromagnetic wave scattering from randomly rough surfaces, from vegetation canopies, and from cylinders are important and ongoing research topics.