Abstract

Overview

In the study of the interaction between microwave radiation and human beings, the traditional view of skin primarily as a water-filled absorber is challenged. Recent findings demonstrate that a part of the skin known as the sweat duct functions similarly to a helical antenna in the sub-terahertz (THz) band.

Findings

• The reflectance of human skin in this frequency range is influenced by the intensity of perspiration, which relates directly to the conductivity of the sweat ducts. This varies under different stress conditions—physical, mental, and emotional.
• Additionally, findings include the detection of circular dichroism in skin reflectance, indicative of the axial mode of a helical antenna.
• A link was established between the sub-THz reflection coefficient of human skin and certain electrocardiography (ECG) parameters.
• A sophisticated simulation tool considering the multi-layer structure of the skin and the embedded helical sweat duct was developed, showing a high specific absorption rate (SAR) in extremely high frequency bands.

Conclusion

This study raises significant concerns regarding the unchecked use of sub-THz technologies in wireless communication, highlighting the need for thorough public health investigations before widespread adoption. The findings underline potential non-thermal biological effects on human skin due to exposure to sub-THz waves, particularly those used in upcoming 5G technologies.