Impact of the hand on the specific absorption rate in the head

In this article, we have investigated the influence of the hand on the Specific Absorption Rate (SAR) in the head for single and dualantenna mobile terminals. The SAR in the head has been evaluated via Finite Difference Time Domain (FDTD) numerical computations. In the numerical models, the user has been represented not only by using the Specific Anthropometric Mannequin (SAM) head phantom, but also by including a hand phantom. Two types of hand grips (soft and firm) have been used to investigate the impact of the hand on the SAR. Moreover, the influence of the index finger position on the SAR has been investigated by using hand models with different locations of the index finger. At low band, the SAR evaluation in the head without including the hand phantom overestimates the actual value, with the hand phantom presents independently on the type, location and number of antennas. The highest overestimation of 50% has been observed for the mobile terminal with bottom positioned Folded J Antenna (FJA). At the high band and when considering the dual-antenna mobile terminals, the hand increases the SAR in the head by up to 40% compared to the respective calculated values without a hand phantom. Further, the SAR evaluation when the firm hand grip is used can be considered as a worst case estimation, because higher SAR values in the head have been obtained compared to when using the soft phantom.