Evaluation of the error induced by an incorrect positioning of the handset against the SAM phantom for SAR calculations

Inter-laboratory comparisons of Specific Absorption Rate (SAR) calculations sometimes show discrepancies between the results. An incorrect positioning of the handset against the head phantom may be one of the possible causes of the observed discrepancies. In order to evaluate the error induced by an incorrect positioning of the device, two commercially available mobile phones with different antenna configurations - one with a built-in PIFA (Planar Inverted-F Antenna) and the other with an external helicoidal antenna- are herein selected for SAR calculations using the SAM (Specific Anthropomorphic Mannequin) head phantom. Using the initial handset/phantom position defined by international dosimetric standards as the reference configuration considered to be correct, several incorrect but nonetheless acceptable handset/phantom configurations are generated and the computed SAR values compared. Results show that deviations with respect to the reference positions may induce up to about 8% difference in the maximum 10°g averaged SAR values in the case of the mobile phone with the external helicoidal antenna.