The human skin as a sub-THz receiver – Does 5G pose a danger to it or not?

• Published in: Environmental research Vol. 163; pp. 208 - 216
• Main Authors: Betzalel, Noa, Ben Ishai, Paul, Feldman, Yuri
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01-05-2018
• Subjects: ANTENNAS; BIOLOGICAL RADIATION EFFECTS; CORRELATIONS; DICHROISM; DUCTS; Helical antenna; Human skin, Sub-Terahertz (sub-THz); MICROWAVE RADIATION; PUBLIC HEALTH; RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; RESOURCE EXPLOITATION; SKIN; Specific Absorption Rate (SAR); SWEAT; Sweat duct; TEMPERATURE DEPENDENCE; Helical antenna; Sweat duct; 5G; Specific Absorption Rate (SAR); Human skin, Sub-Terahertz (sub-THz)
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2018.01.032

In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. In previous works, we showed that this view is flawed when we demonstrated that the coiled portion of the sweat duct in upper skin layer is regarded as a helical antenna in the sub-THz band. Experimentally we showed that the reflectance of the human skin in the sub-THz region depends on the intensity of perspiration, i.e. sweat duct's conductivity, and correlates with levels of human stress (physical, mental and emotional). Later on, we detected circular dichroism in the reflectance from the skin, a signature of the axial mode of a helical antenna. The full ramifications of what these findings represent in the human condition are still unclear. We also revealed correlation of electrocardiography (ECG) parameters to the sub-THz reflection coefficient of human skin. In a recent work, we developed a unique simulation tool of human skin, taking into account the skin multi-layer structure together with the helical segment of the sweat duct embedded in it. The presence of the sweat duct led to a high specific absorption rate (SAR) of the skin in extremely high frequency band. In this paper, we summarize the physical evidence for this phenomenon and consider its implication for the future exploitation of the electromagnetic spectrum by wireless communication. Starting from July 2016 the US Federal Communications Commission (FCC) has adopted new rules for wireless broadband operations above 24 GHz (5 G). This trend of exploitation is predicted to expand to higher frequencies in the sub-THz region. One must consider the implications of human immersion in the electromagnetic noise, caused by devices working at the very same frequencies as those, to which the sweat duct (as a helical antenna) is most attuned. We are raising a warning flag against the unrestricted use of sub-THz technologies for communication, before the possible consequences for public health are explored.
•The sweat duct is regarded as a helical antenna in the sub-THz band, reflectance depends on perspiration.•We outline the background for non-thermal effects based on the structure of sweat ducts.•We have introduced a realistic skin EM model and found the expected SAR for the 5G standard.