In this paperthe numerical modeling of composite materials in view of Nondestructive Testing is considered. The composite material is assumed to be modeled at the macroscopic scale by a possibly complex dielectric permittivity tensor. The material is probed by means of an electromagnetic field having wavelength much larger than the relevant geometrical dimensions. As well known, the numerical modeling is critical especially in this “low-frequency” regime where a strong ill-conditioning of the relevant stiffness matrix typically occur (the so-called low-frequency breakdown problem). The proposednumerical model is robust w.r.t. this underlying ill-conditioning.