Forward and Inverse Bruggeman Formalisms
Suppose that identical spherical particles made of a certain linear material are randomly dispersed in a linear host material. Let the particle radius be less than a tenth of the minimum wavelength in the two materials. Then the particle is electrically small  and the particulate composite material can be considered as an effectively homogeneous material.
The mathematical procedure to predict the effective constitutive dyadics of the composite material from the constitutive dyadics of its constituent materials is called homogenization . Many homogenization formalisms exist, of which the Bruggeman formalism is perhaps the most widely used. This formalism has been extended to the homogenization ...