Parametric SAR study for 4G cellular phone applications

Multiple-Input Multiple-Output antenna structures in mobile terminals constitute an important part of advanced LTE communication services employing carrier aggregation in serving users with multiple band transmission at high data rates. In that sense, 4G/LTE system utilize at least two-antenna diversity system for mobile communication. Considering factors such as the move towards cloud computing and online storage of information in cloud services requiring both receive and transmit modes of operation in multiple bands, mobile phones with two antennas often raise the issue of specific absorption rate in diversity antenna operation. In this study, SAR characteristics of a PIFA antenna element is investigated as the cellular antenna when operated next to a standard specific anthropomorphic mannequin head model in various relative positioning of antenna and mobile terminal. In conclusion, while the opposite does not raise a concern, positioning the antenna on the upper part of the phone was seen to degrade the terminal and radiational characteristics of the antenna and produce average SAR values higher than standard maximums at the operational 4G frequencies of 2.1 and 2.6 GHz. Relatively low SAR values are obtained for 10g averaging scheme and tilted holding position.