Comparison and evaluation of electromagnetic absorption characteristics in realistic human head models of adult and children for 900-MHz mobile telephones

The controversy on the dosimetry in childrenʹs heads for mobile telephones is still inconsistent. Gandhiʹs group [1996, 2002] reported a considerable increase of the spatial peak specific absorption rate (SAR) in childrenʹs heads, while Kusterʹs group [1998] claimed that there was not a significant difference in the SAR between children and adults. In this paper, based on Japanese childrenʹs statistical data on external shapes of heads, we developed two kinds of childrenʹs models from a Japanese adult head model. Using the childrenʹs head models, we calculated the local peak SAR under the same conditions as those previously employed by Gandhiʹs and Kusterʹs groups. Compared to the local peak SAR in the adult head model, we found a considerable increase in the childrenʹs heads when we fixed the output power of the monopole-type antenna, but no significant differences when we fixed the effective current of the dipole-type antenna. This finding suggests that the contradictory conclusions drawn by the above two groups may be due to the different conditions in their numerical peak SAR calculations.