Davis C, Balzano Q (2009) The International Intercomparison of SAR Measurements on Cellular Telephones. IEEE Transactions On Electromagnetic Compatibility.
The paper describes the results of an international comparison of specific absorption rate (SAR) measurements made with wireless telephones. The current compliance testing procedures for hand-held wireless telephones require that manufacturers assess the maximum near-field exposures that they might produce in the head of a phone user. Federal Communications Commission guidelines currently specify that the maximum specific absorption rate (SAR) averaged over 1 g of tissue should not exceed 1.6 W/kg. Testing uses a phantom model that is manufactured as a thin non-absorbing shell shaped with the anatomic contours of the human head and torso, and filled with a dissipative fluid whose dielectric properties are representative of the worst-case RF absorption in the human head. The rationale of this approach is that if SAR guidelines are not exceeded in the phantom, then they will not be exceeded in the more complex structure of a real human head.
A total of 17 laboratories performed independent measurements. Standard testing procedures were used. Two representative wireless phones were used: a Motorola Model V290 phone and a Nokia Model 6310. Each phone was operated at its maximum power at the appropriate frequencies, in the 900- and 1800-MHz bands, for phone positions by the phantom described as “cheek” and “tilt,” for both the left and right ear positions. Laboratories made a total of 32 measurements.
Results are presented graphically in the paper. Maximum SAR values averaged over a 1 cubic cm cube and a 10 cubic cm cube, which correspond to 1 and 10 g cubes of the appropriate density. In general, cheek SARs were higher than tilt SARs, 1-g SARs were higher than 10-g SARS, and 900-MHz SARs were higher than 1800-MHz SARs. Measurements were consistent across laboratories.
Discussion and conclusion
Overall, the results of the inter-comparison support the reliability of the SAR measurement method currently adopted by the phone manufacturers and the regulating governmental agencies.