FDTD assessment of human exposure to electromagnetic fields from WiFi and bluetooth devices in some operating situations

Abstract

In this work, the numerical dosimetry in human exposure to the electromagnetic fields from antennas of wireless devices, such as those of wireless local area networks (WLAN) access points or phone and computer peripherals with Bluetooth antennas, is analyzed with the objective of assessing guidelines compliance. Several geometrical configurations are considered to simulate possible exposure situations of a person to the fields from WLAN or Bluetooth antennas operating at 2400 MHz. The exposure to radiation from two sources of different frequencies when using a 1800 MHz GSM mobile phone connected via Bluetooth with a hands-free car kit is also considered. The finite-difference time-domain (FDTD) method is used to calculate electric and magnetic field values in the vicinity of the antennas and specific absorption rates (SAR) in a high-resolution model of the human head and torso, to be compared with the limits from the guidelines (reference levels and basic restrictions, respectively). Results show that the exposure levels in worst-case situations studied are lower than those obtained when analyzing the exposure to mobile phones, as could be expected because of the low power of the signals and the distance between the human and the antennas, with both field and SAR values being far below the limits established by the guidelines, even when considering the combined exposure to both a GSM and a Bluetooth antenna.

Effects of Early-Onset Radiofrequency Electromagnetic Field Exposure (GSM 900 MHz) on Behavior and Memory in Rats

“…Several studies have been published regarding exposures from novel sources and exposure scenarios (Foster, 2007;Martinez-Búrdalo et al, 2009) and others are ongoing. With multiple sources, a great number of scenarios could potentially be considered.…”

Exposure Minimization in Indoor Wireless Networks

“…In [1] and [6], the impact of densely deployed WiFi networks on the generated exposure levels is investigated. In [7], a finite-difference time domain algorithm is developed for SAR computations by terminal devices in WiFi and Bluetooth networks. The concept of green cellular is highlighted in [8], and it is shown that the required transmit power of indoor terminal devices is reduced when microcell or macrocell systems extend their indoor coverage by deploying low-power stations within the building (femtocells).…”

A Comparison of RF Exposure in Macro- and Femtocells

“…The European Commission, the American National Standards Institute (ANSI) and the Institute of Electrical and Electronics Engineering (IEEE) have defined limits on the RF exposure for the general public [21], [22]. The limits are frequency dependent: for the 1.9 GHz cellular band, the limits are stated in terms of the specific absorption rate (SAR), averaged over a volume containing 10 g of tissue and over any 6 minute period [22].…”