In Vivo Human Skin Dielectric Properties Characterization and Statistical Analysis at Frequencies From 1 to 30 GHz

Abstract

Precise data acquisition and modeling of healthy dermal dielectric properties are critical for accurate skin anomaly detection studies. For this purpose, an extensive campaign of around 1000 measurements across a band of 1-30 GHz leads to the conclusion that each skin region of interest (ROI) provides unique dielectric properties. Therefore, a single-skin model would not suffice to represent the complete human body. The acquired dielectric data are predominantly from the skin layer; however, considering the sensing depth of the utilized coaxial cable, the subcutaneous layers do have a minor contribution toward the effective dielectric properties seen at the probe/skin interface. Palmar skin has the maximum mean absolute percentage deviation in dielectric properties (around 34%) with respect to hand dorsum skin. The remaining measured ROIs (anterior wrist and anterior forearm) generate 4% and 8% dielectric deviation, respectively. Furthermore, female dermal dielectric constant values are observed to be on an average 9% higher across all measured ROIs compared with respective male skin. Subsequent statistical analysis of the measured data leads to the conclusion of a significant dielectric constant dependence on gender. The skin type generates a moderate but insignificant correlation with conductivity values. A similar analysis of volunteer weight and age details determined a weak association with the measured data.