Proper interpretation of source excitations for resolving ostensible excessive power gains of metamaterial resonances

The aim of this communication is to resolve the anomalous phenomenon of extremely large radiated powers of antennas embedded within metamaterial layers apparently achievable under resonances. The essence of the discussion rests on the law of power conservation and causality conditions. A slotted spherical dipole coated with two layers of homogeneous materials is chosen to illustrate the concepts, and the classical approach for solving boundary-value problems via separation of variables is used to treat the structure.