There has not been a great deal of research conducted in this area, but there has been some.
Daniel W. Engels, director of the University of Texas at Arlington‘s Radio Frequency Innovation and Technology Center, and an associate professor in the college’s Department of Electrical Engineering, wrote a paper along with Darmindra D. Arumugam—then a student at the university, now a graduate—entitled “Specific Absorption Rates in the Human Head and Shoulder for Passive UHF RFID Systems at 915 MHz.” Their research revealed that in an ideal absorption environment, an RFID reader located 10 centimeters (3.9 inches) from the human head presents a specific absorption rate above 1.6W/kg for both the spatial-peak 1 g and 10 g cube of tissue—the maximum value allowed by the United States’ Federal Communications Commission (FCC).
“The basic result of all of our work is that really close proximity to UHF [ultrahigh-frequency] RFID readers has potential health issues, particularly when close to the eyes,” Engels wrote in response to my question regarding the potential harmful effects of RFID on the human body. “The eyes are perhaps the most vulnerable part of our bodies to RF radiation.”
To avoid any potential harm to humans, Engels said, UHF RFID interrogators should be set back at least 0.5 meter (1.6 feet) from anyone who might receive constant exposure. He suggests having the read zone cover the body below the neck, which is presumably where the tag would be placed. He adds: “Don’t put a big ‘LOOK HERE!’ sign on the reader antenna.”
If the interrogator is within legal power output limits, and is kept at least 1 meter (3.3 feet) from the human body, the incident radiation—even on the eyes—is at a level well below maximum allowable levels. Engels cautions against turning reader emissions on and off to reduce RF exposure, noting that his early-stage research indicates this could have an impact on pacemakers.
—Mark Roberti, Founder and Editor, RFID Journal
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