SAR Evaluation of portable wireless communication devices using Fractional Body Models -I

Abstract

Nowadays, human safety under RF exposure due to the wireless communication devices is a major concern in the general public. Some of these devices are designed to attach closely to the human body; the concern is further extended to different parts of the whole body. This project is hence to investigate the Specific Absorption rate (SAR) on the human body exposure under the electromagnetic field generated by common wireless communication devices and to verify whether the fractional body model can be used in an efficient SAR evaluation. A simulation based on FDTD has been used to investigate the effect of SAR on human under the radiations from 5 wireless communication devices, which includes GSM 900, PCS 1800, 3G, WLAN, and LTE. The fractional human body models, head, hand, leg and fractional head and hand together with the device model which represent the practical situations of user have also been used since the full body model in the simulation is very complex and time consuming. Results have showed that all the devices evaluated satisfied the spatial peak SAR limit of 2W/kg as specified in ICNIRP guideline. RF energy in the body is generally more concentrated in a relatively small area for devices operating in higher frequency band, such as WLAN. SAR can be underestimated if the complexity of the simulation model is reduced for devices operating in frequency beyond 2.4 GHz. Moreover, the effect of hand cannot be neglected in fractional body modelling. Results have also shown that fractional body model can be used as an efficient SAR evaluation, as the simulation time can save up to 89 % when compared to the full body model.