Millimetric radiometry for measuring human and porcine skin reflectance

Despite the rising interest in the human skin signature over the millimetre wave band there is relatively little information about the human skin reflectance and the dielectric properties of the human skin, and how these varying with locations and between gender, and hydration level of the skin. This paper has investigated the reflectance of the human skin over the frequency band 80-100 GHz, and comparing the reflectance of the human skin with the reflectance of porcine skin samples under normal and wet skin conditions. For a sample of 60 healthy participants (36 males and 24 females) the mean reflectance of the skin over all measurement locations was found to be ~0.606 with a standard deviation of ~0.086. The skin regions of the palm of the hand, the outer wrist and the dorsal forearm skin had reflectances 0.068, 0.058 and 0.0677 lower than the skin regions of the back of the hand, the inner wrist and the volar forearms respectively. Reflectance measurements of human skin under normal and wet state on the palm of the hand and the back of the hand regions indicate that the mean differences in the reflectance before and after the application of water is ~0.15 and ~0.075 respectively. A comparison in reflectance between human skin and porcine skin samples indicates similar trends in signatures between ex-vivo porcine skin samples and human skin. During the cycle of life, human skin is affected by many factors such as the age, the environment, the interaction with different types of radiation, genetic defects, dehydration, and accidents. These factors might cause diseases, temporal skin conditions, and permanent disorders. In response to this, the skin presents signatures, which can be measured using non-contact millimetre wave sensors that could quantify the degree of the damage. These unique findings enable millimetre wave radiometry to be used for detecting human skin signatures and anomalies under different conditions by identify unusually high or low levels of reflectance in tens of seconds.