Asymptotic formulas for perturbations in the eigenfrequencies of the full Maxwell equations due to the presence of imperfections of small diameter

We consider electromagnetic media that consist of a homogeneous (constant coefficient) electromagnetic material with a finite number of small dielectric imperfections. For such media, we provide a rigorous derivation of asymptotic formulas for perturbations in the eigenfrequencies of the full Maxwell equations caused by the presence of the dielectric imperfections.