Pulse Radiator in Free Space

Pulse radiator in free space is a suitable example to use for deriving the energy separation formulae because all the energies are finite and their performances with respect to the source can be examined rigorously. By analogy with the electromagnetic energy concepts in the classical charged particle theory and using the relationships derived from the Maxwell equations, the total electromagnetic energy of a pulse radiator is divided into three parts. The first part is the Coulomb-velocity energy. It disappears immediately after the source has disappeared. The second part also disappears a short while later after the source has disappeared. It is called the macroscopic Schott energy in this book because its behavior is similar to the Schott energy in the charged particle theory. The third part is the radiative electromagnetic energy which keeps propagating in free space till it encounters other sources. The energy separation formulae for time harmonic waves are also available. The results in time domain and frequency domain are completely in consistent because they are respectively derived from the time domain Maxwell equations and the frequency domain Maxwell equations directly. It is also verified with the Hertzian dipole both in frequency domain and in time domain.