This paper presents a study of dielectric properties of some ceramic/polymer composites. It is also emphasizes the polarization of relaxation phenomena, based on the frequency variation of complex permittivity of the compounds. Based on the comparison between experimental and theoretical results, it has been established that the best theoretic formula for the approximation of the static permittivity as a function of the compounds properties, for a binary mixture with very different dielectric permittivities, is Lichtenecker-Rother formula.