This paper discusses the suitability of different standardized approaches for product compliance assessments of low power radio base stations with respect to general public whole-body radiofrequency exposure limits. Using numerical simulations, two standardized procedures based on spatially averaged field strengths, for comparison against the reference levels, and based on SAR assessments, for comparison against the basic restrictions, are evaluated in the frequency range 300 MHz - 5000 MHz. It is shown that the currently standardized whole-body SAR measurement procedure is overly conservative for small phantom-antenna separation distances and may lead to unphysical results. To avoid these problems, a new distance dependent correction factor is proposed to account for effects of tissue layering. Furthermore, a new box-shaped phantom for child whole-body SAR measurements is proposed which may be used to obtain more accurate whole-body SAR results compared with currently standardized procedures. The proposed approach is shown to produce conservative results with respect to numerical simulations using the anatomical child phantom Roberta from the Virtual Classroom set of phantoms.
Thors, B.; Nord, L. ; Colombi, D. ; Tornevik, C