Electromagnetic energy around Hertzian dipoles

There is great interest in the fundamental question of how an antenna radiates and where is the source of its radiation. Most examinations have focused on tracing radiation back to "radiation centers" on an antenna. The aim of this paper is to show how to determine where static and reactive energies are converted into radiation in the fields around an antenna. The origin of radiation is well understood on a qualitative basis. To answer the question more precisely, the authors present a new technique for analysing how electromagnetic energy behaves, called the method of "causal surfaces".