A quantitative approach to the dielectric properties of the skin.

The results of measurements using an open-ended coaxial probe of the audio/radiofrequency dielectric properties of human skin in vivo, either dry or moistened with physiological saline, are reported. Permittivity and conductivity dispersion curves were parametrized by using a newly reported dispersion function (Raicu V 1999 Dielectric properties of biological matter: model combining Debye-type and 'universal' responses Phys. Rev. E 60 4677), and the results obtained are discussed in the light of the recent advances in this field. It is suggested that the coaxial probe reports on the properties of the superficial layer, the stratum corneum, when the skin surface is dry, whilst the signal from deeper skin layers becomes dominant after wetting the skin with conductive physiological saline.