Antennas and propagation

Abstract

A section at the start of this chapter, devoted to sources, potentials and fields, introduces the vector magnetic potential, the Lorentz condition (or Lorentz gauge) and retarded potentials. It is pointed out that wire antenna problems usually require the retarded potential, from which the electric and magnetic fields can be determined, to be found for one or more sources. An analysis of the Hertzian dipole is carried out and, taking this dipole as an example, some properties common to any antenna type are discussed. Near-and far-field regions, power radiated as calculated from Poynting’s theorem presented in Chapter 1, radiation resistance, directional characteristics, radiation intensity, directive gain, directivity and far-field radiation patterns are discussed.