Constituents of power of an electric dipole of finite size

摘要

An electric dipole of finite size in the form of a spherical current sheet with a surface current density in the theta direction varying as sin theta is introduced. External to the spherical surface, the electromagnetic fields are of the same form as that of a point electric dipole situated at the origin and oriented in the z direction. The power and the power flux density are separated into the radiative and the reactive parts. This type of separation of power is related to the usual separation made on the basis of propagating and evanescent waves. There is a natural relationship between the radiative and the reactive parts with the far-field and the near-field effects, respectively. (C) 2008 Optical Society of America.