A surrogate model to assess the whole body SAR induced by multiple plane waves at 2.4 GHz
- 210 Downloads
The assessment of the exposure to electromagnetic waves is nowadays a key question. Dealing with the relationship between exposure and incident field, most of previous investigations have been performed with a single plane wave. Realistic exposure in the far field can be modeled as multiple plane waves with random direction of arrival, random amplitude, and random phase. This paper, based on numerical investigations, studies the whole body specific absorption rate (SAR) linked to the exposure induced by five random plane waves having uniformly distributed angles of arrival in the horizontal plane, log-normal distributed amplitudes, and uniformly distributed phases. A first result shows that this random heterogeneous exposure generates maximal variations of ±25% for the whole body specific absorption. An important observation is that the exposure to a single plane wave arriving face to the body, used for the guidelines, does not constitute the worst case. We propose a surrogate model to assess the distribution of the whole body SAR in the case of an exposure to multiple plane waves. For a sample of 30 values of whole body SAR induced by five plane waves at 2.4 GHz, this simple approach, considering the resulting SAR as the sum of the SAR induced by each isolated plane wave, leads to an estimated distribution of whole body SAR following the real distribution with a p value of 76% according to the Kolmogorov statistical test.
KeywordsRadiofrequencies Surrogate model Specific Absorption Rate (SAR) FDTD Statistical tests Multiple plane waves exposure
This work was sponsored by the Agence Nationale de la Recherche in the framework of the Mutlipass project (whist.institut-telecom.fr).
- 1.ICNIRP (1998) Guidelines for limiting exposure to time varying electric magnetic and electromagnetic field (up to 300 GHz). Radiat Prot Health Phys 74:494–522Google Scholar
- 5.Dimbylow PJ (1996) The development of realistic voxel phantoms for electromagnetic field dosimetry Proc Int. Workshop on Voxel Phantom Development (National Radiological Protection Board Report) pp 1–7Google Scholar
- 7.Neubauer G, Cecil S, Preiner P, Mitrevski N, Vermeeren G, Wout J, Martens L, Kuehn S, Kuster N (2006) The relation between SAR and the electromagnetic field distribution for heterogeneous exposure conditions, EUCAP, The First European Conference on Antennas and Propagation, 6–10 November 2006, Nice, Proceeding CDGoogle Scholar
- 8.Georg Neubauer et al. The relation between the specific absorption rate and electromagnetic field intensity for heterogeneous exposure conditions at mobile communications frequencies. Bioelectromagnetics 30(8):651–662Google Scholar
- 13.Christ A, Kainz W, Hahn E, Honegger K, Shen J, Rascher W, Janka R, Bautz W, Kiefer B, Schmitt P, Hollenbach H, Chen J, Kam A, Neufeld E, Oberle M, Kuster N (2007) The virtual family project-development of anatomical whole-body models of two adults and two children. Proceedings of the 23rd Annual Review of Progress in Applied Computational Electromagnetics (ACES)Google Scholar
- 15.Gabriel C et al. (1996) Compilation of the dielectric properties of body tissues at RF and microwave frequencies. Brooks Air Force Technical Report AL/OE TE (1996–0037)Google Scholar
- 17.Taflove A, Hagness S (2005) Computational electrodynamics: the finite-difference time-domain method, 3rd edn. Artech House Publish, Norwood, MAGoogle Scholar
- 23.Gerald CF, Wheatley PO (1994) Applied Numerical Analysis, 5th ed. Reading, MA: Addison-Wesley, ch. 10, pp 696–748Google Scholar