A brain‐equivalent solid phantom and its application to SAR estimation by the thermographic method

Abstract

Recently, with the rapid proliferation of mobile communication devices, the effects of electromagnetic waves on the human body have drawn attention. Although these effects depend significantly on frequency, the thermal effects due to absorption of the electromagnetic energy are considered predominant at microwave frequencies. In general, as the guideline for the thermal effects, the power per unit mass absorbed in the biological body, namely, the specific absorption rate (SAR [W/kg]), is used. Cellular phones are employed in close proximity to the head where vital functions of the body are concentrated. Even if the output is weak, there is the possibility that the power absorption may become locally excessive. Therefore, it is extremely important from a safety point of view to establish an experimental evaluation procedure regarding the SAR for the human head. In this paper, the characteristics of thermography are recognized by means of which the surface SAR can be measured, and thus the SAR distribution in an arbitrarily shaped medium. Using the biologically equivalent phantom developed in the authors' laboratory for improving the conventional phantom used for the same purpose, a fundamental investigation is carried out as to how accurately the SAR distribution can be measured. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(12): 24–34, 2000