Microwave Characterization and Probe Sensing: Parametric Study with Skin Phantom Thickness

Novel microwave and millimeter-wave devices have been recently investigated as promising diagnostic aids for skin anomaly detection. These devices rely on knowledge of skin dielectric parameters. Skin thickness varies with body location, and, hence, the goal of our work is to characterize the dielectric skin properties in the microwave range as a function of skin thickness. To do so systematically, and in a controlled laboratory environment, we developed skin phantoms models ranging from 0.5 mm to 5 mm in thickness, with 0.5 mm increments. These phantoms are placed on a fat-mimicking material and then characterized with the Keysight slim form probe over the 0.5–2.6 GHz range. Our results indicate that skin thickness, usually known from extensive anatomical resources, should be taken into account for proper interpretation of eventual dielectric characterization in vivo, as the probe's sensing volume is likely to include a complex, multi-tissue dielectric distribution.