Mechanisms of RF Electromagnetic Field Absorption in Human Hands and Fingers

The absorption of electromagnetic fields in the hand is investigated over the 900-3700-MHz frequency range. This enables the determination of the envelope of the peak spatial specific absorption rate in the hand. It also provides a basis for deriving measurement procedures for evaluating compliance of wireless devices with specific absorption rate limits in the hands. Both plane waves and dipole antennas are used to investigate the patterns of RF absorption in hand and finger tissue models for far- and near-field exposures. The results demonstrate that absorption enhancements are found in the hand that are not present in a standardized flat phantom. Enhancements of several decibels are observed, depending on the model parameters. A method to conservatively estimate the exposure in the hand based on flat phantom measurements is proposed.