Impact of pinna compression on the RF absorption in the heads of adult and juvenile cell phone users

The electromagnetic exposure of cell phone users depends on several parameters. One of the most dominant of these is the distance between the cell phone and the head tissue. The pinna can be regarded as a spacer between the top of the phone and the head tissue. The size of this spacer has not yet been systematically studied. The objective of this article is to investigate the variations of distance as a function of age of the exposed person, and the mechanical force on the pinna and how it affects the peak spatial specific absorption rate (psSAR). The distances were measured for adults and children (6-8 years of age) while applying a well-defined force on the pinna using a custom-developed measurement device. The average distances of the pinnae to the heads and their standard deviations showed no major differences between the two age groups: 10.5 +/- 2.0 mm for children (6-8 years) and 9.5 +/- 2.0 mm for adults. The pinnae of our anatomical high-resolution head models of one adult and two children were transformed according to the measurement results. The numerical exposure analysis showed that the reduced distance due to the pinna compression can increase the maximum 10 g psSAR by approximately 2 dB for adults and children, if the exposure maximum is associated with the upper part of the phone.

[1]  Luc Martens,et al.  Electromagnetic safety of children using wireless phones: A literature review , 2005, Bioelectromagnetics.

[2]  N. Kuster,et al.  Differences in RF energy absorption in the heads of adults and children , 2005, Bioelectromagnetics.

[3]  N. Kuster,et al.  Energy absorption mechanism by biological bodies in the near field of dipole antennas above 300 MHz , 1992 .

[4]  A. Faraone,et al.  Comparisons of computed mobile phone induced SAR in the SAM phantom to that in anatomically correct models of the human head , 2006, IEEE Transactions on Electromagnetic Compatibility.

[5]  N. Kuster,et al.  Appropriate modeling of the ear for compliance testing of handheld MTE with SAR safety limits at 900/1800 MHz , 2000 .

[6]  C. Gabriel,et al.  Variation of the dielectric properties of tissues with age: the effect on the values of SAR in children when exposed to walkie–talkie devices , 2009, Physics in medicine and biology.

[7]  Niels Kuster,et al.  The Virtual Family—development of surface-based anatomical models of two adults and two children for dosimetric simulations , 2010, Physics in medicine and biology.

[8]  J. Wiart,et al.  Analysis of RF exposure in the head tissues of children and adults , 2008, Physics in medicine and biology.

[9]  Reilly Jp.  Comments concerning "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)". , 1999 .

[10]  R. W. Lau,et al.  The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues. , 1996, Physics in medicine and biology.

[11]  D. W. Scott.  On optimal and data based histograms , 1979 .

[12]  Niels Kuster,et al.  Dosimetric comparison of the specific anthropomorphic mannequin (SAM) to 14 anatomical head models using a novel definition for the mobile phone positioning , 2005, Physics in medicine and biology.