FDTD calculation of whole-body average SAR in adult and child models for frequencies from 30 MHz to 3 GHz.
Due to the difficulty of the specific absorption rate (SAR) measurement in an actual human body for electromagnetic radio-frequency (RF) exposure, in various compliance assessment procedures the incident electric field or power density is being used as a reference level, which should never yield a larger whole-body average SAR than the basic safety limit. The relationship between the reference level and the whole-body average SAR, however, was established mainly based on numerical calculations for highly simplified human modelling dozens of years ago. Its validity is being questioned by the latest calculation results. In verifying the validity of the reference level with respect to the basic SAR limit for RF exposure, it is essential to have a high accuracy of human modelling and numerical code. In this study, we made a detailed error analysis in the whole-body average SAR calculation for the finite-difference time-domain (FDTD) method in conjunction with the perfectly matched layer (PML) absorbing boundaries. We derived a basic rule for the PML employment based on a dielectric sphere and the Mie theory solution. We then attempted to clarify to what extent the whole-body average SAR may reach using an anatomically based Japanese adult model and a scaled child model. The results show that the whole-body average SAR under the ICNIRP reference level exceeds the basic safety limit nearly 30% for the child model both in the resonance frequency and 2 GHz band.
Wang
Jianqing
J
Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan. wang@nitech.ac.jp
Fujiwara
Osamu
O
Kodera
Sachiko
S
Watanabe
Soichi
S
D000328:Adult; D000465:Algorithms; D002648:Child; D003198:Computer Simulation; D004574:Electromagnetic Fields; D020342:Finite Element Analysis; D006801:Humans; D007564:Japan; D008953:Models, Anatomic; D011829:Radiation Dosage; D011846:Radio Waves; D012062:Relative Biological Effectiveness; D014915:Whole-Body Counting / Q000379:methods*; D014916:Whole-Body Irradiation