On the effects of straight metallic jewellery on the specific absorption rates resulting from face illuminating radio communications devices at popular cellular frequencies

This paper presents simulated and measured phantom results for the possible effects that head worn jewellery may have on the relative levels of energy absorbed in the human head with cellular enabled mobile communication devices. The FDTD electromagnetic code used with simple and complex anatomical mathematical phantoms was used to consider the interactions of metallic jewellery, heads and representative sources at 900 and 1800 MHz. Illuminated metallic pins of different lengths were positioned in front of the face. Initially, a homogenous phantom was used to understand the relative enhancement mechanisms. This geometry allowed the results to be validated with the industry standard DASY4 robot SAR measurement system related to the CENELEC head. Jewellery pins were then added to an anatomically realistic head. The relative increase in the 1 g and 10 g SAR, due to a pin with a length 0.4λ near the eyebrows of a complex, anatomically realistic head was approximately three times at 1800 MHz. Such pins increased the SAR averaged over a 1 g or 10 gmass by redistributing the energy absorbed inside the head and focusing this energy towards the area of the head nearest to the centre of the pin. Although, the pins increased the SAR, the SAR standards were not breached and the jewellery produced lower values than those of previous studies when the source was positioned close to the ear.