Title :
Evaluation of the SAR distribution in the human head for cellular phones used in a partially closed environment
Author :
Bernardi, Paolo ; Cavagnaro, Marta ; Pisa, Stefano
Author_Institution :
Dept. of Electron. Eng., Rome Univ., Italy
fDate :
8/1/1996 12:00:00 AM
Abstract :
The purpose of this paper is to calculate the specific absorption rate (SAR) distribution in a human head exposed to the electromagnetic field emitted from a handheld cellular phone operating in the 900 MHz range in a partially closed environment. The environment could be, for example, the interior of a car, a condition of exposure which is largely diffused nowadays. The presence of reflecting surfaces near the phone modifies the current distribution on, and the emitting properties of, the phone antenna. Therefore, the distribution of the absorbed power inside the head is different from that absorbed in the free space exposure condition. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in a realistic anatomically based model of the human head for different antenna-handset configurations and for different antenna-head distances. The environmental effects have been simulated through partially or totally reflecting walls located in various positions with reference to the phone. It is found that the presence of a horizontal reflecting wall over the head decreases the SAR values in the part of the head directly exposed to the phone antenna, while it increases the SAR values in the part not directly exposed. On the contrary, the presence of a vertical wall, located in proximity of the phone and parallel to it, raises the SAR values everywhere into the head
Keywords :
biological effects of fields; cellular radio; current distribution; electromagnetic wave absorption; electromagnetic wave reflection; finite difference time-domain analysis; health hazards; mobile antennas; telephone sets; FDTD method; SAR distribution; UHF; antenna-handset configurations; antenna-head distances; car interior; current distribution; electromagnetic field; emitting properties; environmental effects; finite-difference time-domain; free space exposure condition; handheld cellular phone; horizontal reflecting wall; human head; partially closed environment; phone antenna; reflecting surfaces; reflecting walls; vertical wall; Cellular phones; Dipole antennas; Electromagnetic fields; Finite difference methods; Humans; Probes; Reflector antennas; Specific absorption rate; Time domain analysis; Transmitting antennas;
Journal_Title :
Electromagnetic Compatibility, IEEE Transactions on