4. Conclusion

In this article, after a brief description of the different classes of materials (dielectric, magnetic, conductive), we review the operating principle of the two main procedures usually used to determine the complex permittivity and permeability of massive linear, homogeneous, isotropic (LHI) materials: the single-frequency resonant cavity technique, well suited to low-loss dielectric materials, versus the reflection/transmission method based on the use of a coaxial air line, which is well suited to the problem of broadband measurement of the highly dispersive and dissipative properties of magnetic materials. We highlight the limitations of these conventional techniques for determining the constitutive parameters of materials with singular properties. These singularities may be the shape of the sample to be tested (thin film), or its EM properties, which are not necessarily always linear,...