ABSTRACT
This chapter basically deals with the radiation mechanism. This begins with the escape of energy from an oscillating dipole, which includes loop formation, loop detachment, and the loop expansion. It describes the mathematical aspects of radiation beginning from the retarded (or time-varying) potentials, Maxwell’s equations, and some assumptions. It discusses the field and the radiated power due an oscillating dipole by identifying the components of vector magnetic potential and the components of electric and magnetic fields. The field is classified on the basis of terms involved. Expressions for radiated power, characteristic impedance, and radiation resistance for elemental length, short dipole, and short monopole are obtained. Expressions are also obtained for radiated power and the radiation resistance for far and near fields due to sinusoidal current distribution. In view of the relevant field relations, the radiation patterns for different lengths and orientations are illustrated. The constituents of the radiation pattern are identified and the effects of termination, current distribution, and effects due to the ground on these radiation patterns are also discussed.
