Absorption of millimeter waves by human beings and its biological implications

Journal Article · Sat Feb 01 00:00:00 EST 1986 · IEEE Trans. Microwave Theory Tech.; (United States)

DOI:https://doi.org/10.1109/TMTT.1986.1133316· OSTI ID:5631509

Gandhi, O P; Riazi, A

With recent advances in millimeter-wave technology, including the availability of high-power sources, in this band, it has become necessary to understand the biological implications of this energy for human beings. This paper gives the millimeter-wave absorption efficiency for the human body with and without clothing. Ninety to ninety-five percent of the incident energy may be absorbed in the skin with dry clothing, with or without an intervening air gap, acting as an impedance transformer. On account of the submillimeter depths of penetration in the skin, superficial SAR's as high as 65-357 W/Kg have been calculated for power density of incident radiation corresponding to the ANSI guideline of 5 mW/cm/sup 2/. Because most of the millimeter-wave absorption is in the region of the cutaneous thermal receptors (0.1-1.0 mm), the sensations of absorbed energy are likely to be similar to those of IR. For the latter, threshold of heat perception is near 0.67 mW/cm/sup 2/, with power densities on the order of 8.7 mW/cm/sup 2/ likely to cause sensations of ''very warm to hot'' with a latency of 1.0 +- 0.6 s. Calculations are made for thresholds of hearing of pulsed millimeter waves. Pulsed energy densities of 143/579 ..mu..J/cm/sup 2/ are obtained for the frequency band 30-300 GHz. These are 8-28 times larger than the threshold for microwaves below 3 GHz. The paper also points to the need for evaluation of ocular effects of millimeter-wave irradiation because of high SAR's in the cornea.

• Research Organization: Department of Electrical Engineering, University of Utah, Salt Lake City, UT 84112
• OSTI ID: 5631509
• Journal Information: IEEE Trans. Microwave Theory Tech.; (United States), Vol. 34:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
HUMAN POPULATIONS
HEALTH HAZARDS
MICROWAVE RADIATION
SKIN ABSORPTION
CALCULATION METHODS
CLOTHING
CORNEA
ELECTROMAGNETIC RADIATION
ENERGY DENSITY
GHZ RANGE 01-100
INFRARED RADIATION
POWER DENSITY
THRESHOLD DOSE
ABSORPTION
BODY
BODY AREAS
DOSES
EYES
FACE
FREQUENCY RANGE
GHZ RANGE
HAZARDS
HEAD
ORGANS
POPULATIONS
RADIATION DOSES
RADIATIONS
SENSE ORGANS
UPTAKE
560400* - Other Environmental Pollutant Effects