Temperature and Specific Absorption Rate Distribution in the Human Head Exposed to RF Propagation at Different Distances and Angles

Abstract

Normal 0 21 false false false TR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normal Tablo"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} This paper presents specific absorption rate (SAR) obtained inside a human head and the thermal effects due to exposure to a cellular phone. The cellular phone radiating at 900 MHz and 1800 MHz frequencies was modeled by microstrip patch antenna and its output power was chosen according to the worst-case scenario. By the aid of finite element method (FEM) based COMSOL Multiphysics software program, not only the effect of distance between the antenna and the head model but also the effect of antenna’s angle relative to the head on SAR and the temperature distribution in the head model were investigated. It was shown in the study that the distance and the angle of the antenna to the head had significant importance on the SAR values and the temperature increase in the head. As a result of the simulation, it was found that SAR values at 900 MHz were under the safety limit values whereas at 1800 MHz were under the limits when the distance between the antenna and the head was 0.2 cm. Furthermore, it was noted that the temperature increase on the head was in good agreement with the other studies.