Computational Model of the Influence of an 835 MHz Patch Antenna Distance on Specific Absorption Rate (SAR) and Temperature Change in the Human Head

Abstract

Human exposure to mobile phone radio frequency (RF) radiation has caused public concern for human health. Mobile phone RF exposure depends on many different parameters. The aim of this study is to examine the effects of both the RF source distance from a human head and of output power levels on the temperature change and the Specific Absorption Rate (SAR) in the head. The peak spatially-averaged SAR over 1 g of tissue is also identified to compare the study results to Health Canada’s Safety Code 6 exposure limits. The SAR and temperature change in the head are simulated in this study using a Specific Anthropomorphic Mannequin (SAM) head model with heterogeneous dielectric properties and a microstrip patch antenna operating at a frequency of 835 MHz. The microstrip patch antenna distance from the head is varied from 0-15mm and it is operated at three different time-averaged output power levels. The simulation is performed using COMSOL Multiphysics software and is solved with the Finite Element Analysis (FEA) method. The results show that both SAR and temperature change in the head model increase as the distance between the head model and the patch antenna decreases. The peak spatially-averaged SAR over 1 g of tissue is found to triple as the phone moves from 4mm from the head to 0mm from the head. The results from this study indicate that to mitigate possible health risks from RF radiation mobile phones should be kept at least 4mm from the head.