State of the art methods for low SAR antenna implementation

This paper reviews the different methods employed in the last years for the development of low specific absorption rate (SAR) antennas inside portable terminals of mobile phone systems. Specifically, auxiliary antenna elements, ferrite loading, EBG/AMC surfaces and metamaterials techniques will be examined. From the recent information about the possible health effects of electromagnetic radiation on humans, it is apparent that the SAR reduction techniques have to be improved in order to create practical implementations that allow an extensive use of low SAR mobile phone terminals. Satisfying the bandwidth, efficiency, size and cost requirements of a low SAR solution for the new mobile terminals has not been completely possible so far. Each low SAR technique has limitations and that prevents an extensive use in the mobile terminals available in the market. From the methods reviewed the EBG and metamaterial techniques appear as feasible low SAR options that need more study to improve the size and bandwidth parameters that limits their use.