Microwave Imaging

CHAPTER TWO

Electromagnetic Scattering

2.1 MAXWELL'S EQUATIONS

The electromagnetic field is governed by a set of experimental laws known as Maxwell's equations (Stratton 1941, Jones 1964, Felsen and Marcuvitz 1973, Van Bladel 2007, Chew 1990), which relate the field vectors to their sources. Maxwell's equations can be expressed in the following local forms:

Here r denotes the position vector [in meters (m)] and t the time [in seconds (s)]. and are the vector fields describing the electromagnetic field and are called the electric field [in volts per meter (V/m)], the magnetic flux density [in webers per meter (Wb/m²)], the magnetic field [in amperes per meter (A/m)], and the electric flux density [in coulombs per square meter (C/m²)], respectively. The sources are specified by the volume electric charge density ρ [in coulombs per cubic meter (C/m³)] and by the electric current density ...