Energy flux densities of electromagnetic waves

Abstract In time‐harmonic electromagnetic fields, the Poynting vector, the cross product of electric field with the complex conjugate of the magnetic field, is well known as an energy flux density vector. Here, a new type of vector is proposed in which the cross products of electric and magnetic fields with their corresponding complex conjugates are taken, and its relationship with the Poynting vector is established as a pair of Max‐wellian‐type equations. Moreover, the usefulness of this vector is demonstrated by the examples of optical theorem, reciprocity theorem and decomposition of radiated power into circularly polarized fields, where it supplements the Poynting vector. This vector, like the Poynting vector, can also be considered as the energy flux density vector of the electromagnetic wave.