Mixed quadratic model for peak spatial-average SAR of coherent multiple antenna devices

Specific Absorption Rate (SAR) is a measure of the electromagnetic exposure of portable devices imposed by regulatory agencies. In this paper, we model peak spatial-average SAR of multiple-antenna portable devices using a simple mixed quadratic function of the transmitted vector signal. The model takes into account the movement of location on peak SAR as the transmitted signal varies in amplitude and relative phase between antennas, and can be applied to any number of antennas. Examples with two and four antennas are presented.