An Algorithm for Predicting the Change in SAR in a Human Phantom Due to Deviations in Its Complex Permittivity

The aim of this study is to determine a robust prediction algorithm that can be used to correct the measured specific absorption rate (SAR) in a homogeneous phantom when its complex permittivity deviates from standardized reference values. Results are analyzed over a frequency range of 30-6000 MHz. Both measurements and numerical simulations are presented. Several antenna sizes and distances to the phantom are investigated so as to study a large range of SAR distributions. It is demonstrated that the prediction algorithm, while developed using dipole antennas, also works well for mobile telephone models. Employing the prediction algorithm reduces the SAR measurement uncertainty, thereby improving the reproducibility of SAR compliance assessment between laboratories. Another benefit of the algorithm is that it enables the use of broadband tissue-equivalent liquids, whose dielectric parameters are not currently within the tight tolerances of existing standards. The use of broadband liquids reduces the cost of SAR measurement. The method presented in this paper is of benefit to the IEEE 1528 and IEC 62209 measurement standards.

[1]  C. Gabriel,et al.  Complex permittivity of sodium chloride solutions at microwave frequencies , 2007, Bioelectromagnetics.

[2]  A. Ahlbom.  Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz) , 1998 .

[3]  C. Chou,et al.  Threshold Power of Canonical Antennas for Inducing SAR at Compliance Limits in the 300–3000 MHz Frequency Range , 2007, IEEE Transactions on Electromagnetic Compatibility.

[4]  Jean-Pierre Berenger,et al.  A perfectly matched layer for the absorption of electromagnetic waves , 1994 .

[5]  Sensitivity of the spatial-average peak SAR to the dielectric parameters of media used for compliance testing in the frequency range 0.3 - 3 GHz , 2002, IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313).

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

[7]  James C. Lin,et al.  Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry. , 1996, Bioelectromagnetics.

[8]  C. Di Nallo,et al.  Evaluation of SAR in a homogenous head model for clam-shell type cellular phones , 2006, 2006 IEEE Antennas and Propagation Society International Symposium.

[9]  M. Kanda,et al.  Faster determination of mass-averaged SAR from 2-D area scans , 2004, IEEE Transactions on Microwave Theory and Techniques.

[10]  D. Savitz,et al.  INTERNATIONAL COMMISSION ON NON-IONIZING RADIATION PROTECTION , 2011 .

[11]  N. Kuster,et al.  The dependence of electromagnetic energy absorption upon human head tissue composition in the frequency range of 300-3000 MHz , 2000 .

[12]  A. Peyman,et al.  Development and characterisation of tissue equivalent materials for frequency range 30-300MHz , 2007 .

[13]  Q. Balzano,et al.  Formulation and characterization of tissue equivalent liquids used for RF densitometry and dosimetry measurements , 2004, IEEE Transactions on Microwave Theory and Techniques.

[14]  Shinji Uebayashi,et al.  Influence of Phantom Shell on SAR Measurement in 3-6 GHz Frequency Range , 2005, IEICE Trans. Commun..