Experimental and numerical investigation of the maximum specific absorption rate in a spherical phantom when operating a mobile phone near a metallic wall

A spherical phantom head irradiated with a mobile phone was placed in close proximity to a metallic wall and its specific absorption rates (SARs) were investigated both experimentally and numerically. The main goal of this study was to determine the effect of the reflected electromagnetic fields from the walls on the maximum spatial average 10 g SAR. The mobile phone was modelled as a half-wavelength dipole antenna operating in the 900 MHz range, radiating a constant output power. Two wall arrangements were considered and the change in the SARs with the distance from the wall was recorded. Measured SAR results presented in this work are the first of their kind in the study of the effect of the radio frequency exposure from mobile phones used near metallic walls. Simulated results were obtained using the finite-difference time-domain method. A good agreement between the experiment and the simulation was obtained. When the phantom was placed at a distance of 64 mm from the wall, the SARs obtained were higher than their free-space values by 38, 54 and 82% for the phantom–dipole antenna separation distances of 16, 22 and 30 mm, respectively.