Approximation of Surface-SAR in a Realistic Head Model for Microwave Exposure Using External Magnetic Near-Field

Michihiko NOMURA

IEICE TRANSACTIONS on Communications   Vol.E78-B    No.2    pp.140-144
Publication Date: 1995/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Electromagnetic Compatibility)
microwave bio-effect,  realistic head model,  FD-TD technique,  surface-SAR,  external magnetic near-field,  

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A method is described for approximately estimating the surface specific-absorption-rate (SAR) in an anatomically realistic model of the human head for microwave exposure using the external magnetic near-field. The finite-difference time-domain (FD-TD) technique is used to compute the electromagnetic fields in the head model for 750-MHz and 1.5-GHz far-field exposures with the 1991 ANSI specified safety level. The spatial pattern tracking between the one-gram averaged surface-SAR and external magnetic near-field is demonstrated on the horizontal cross sectional perimeter of the head model. The regression coefficients between them are also obtained on the fifty-five horizontal cross sectional perimeters, which could give an approximate value of the surface-SAR in an acutual head, if the external magnetic near-field would be measured. This is validated by the theoretical results in a semi-infinite homogeneous flat model for normal incidence microwave exposure.