Specific absorption rate and temperature increases in the head of a cellular-phone user

In this paper, a complete electromagnetic and thermal analysis has been per formed considering the head of a subject exposed to various kinds of cellul ar phones available on the market, and focusing the attention on important organs like the eye Lens and brain. Attention has first been posed on a par ticular phone model, and a comparison between the absorbed power distributi on and steady-state temperature increases has been carried out. The influen ce of different antennas (dipole, monopole, whip, and planar inverted F ant enna) on the power absorption and on the consequent tissue heating has then been analyzed. The obtained results show, for a radiated power of 600 mW, maximum SAR values, averaged over 1 g, from 2.2 to 3.7 W/kg depending on th e considered phone. The maximum temperature increases are obtained in the e ar and vary from 0.22 degrees C to 0.43 degrees C, while the maximum temper ature increases in the brain lie from 0.08 degrees C to 0.19 degrees C. The se steady-state temperature increases are obtained after about 50 min of ex posure, with a time constant of approximately 6 min. Finally, the results e vidence a maximum temperature increase in the external part of the brain fr om 0.10 degrees C to 0.16 degrees C for every 1 W/kg of SAR, averaged over 1 g of brain tissue.