Title :
Radiation Characteristics of Ingestible Wireless Devices in Human Intestine Following Radio Frequency Exposure at 430, 800, 1200, and 2400 MHz
Author :
Xu, Lisheng ; Meng, Max Q H ; Ren, Hongliang ; Chan, Yawen
Author_Institution :
Sino-Dutch Biomed. & Inf. Eng. Sch., Northeastern Univ., Shenyang, China
Abstract :
In order to assess the compliance of ingested wireless device (IWD) with related international safety guidelines, the studies on the biological effects and the signal intensity of an IWD in two realistic human body models using the finite-difference time-domain (FDTD) method are reported in this paper. Simulation studies are carried out in 21 scenarios where the IWD is placed at seven positions with three orientations, for each of the two human models. Specific absorption rate (SAR), temperature rise, near fields and far fields are analyzed in the 21 scenarios at four selected operation frequencies of 430 and 800 MHz, and 1.2 and 2.4 GHz, respectively. Our study indicates that the radiation intensity outside of the human body decreases with the increase of operation frequency. Furthermore, the radiation characteristics of the IWD are orientation and position dependent. The polarization of electric field outside of the human body is similar to that of the radio frequency (RF) source. As far as the compliance of safety is concerned, among all the simulated scenarios the maxima of the averaged-1 g and averaged-10 g SARs can reach 3.71 W/kg and 1.37 W/kg at the input power of 25 mW, respectively.
Keywords :
biological effects of fields; electromagnetic waves; finite difference time-domain analysis; biological effects; far fields; finite-difference time-domain method; frequency 1200 MHz; frequency 2400 MHz; frequency 430 MHz; frequency 800 MHz; human body model; human intestine; ingested wireless device; international safety guidelines; near fields; operating frequency; power 25 mW; radiation intensity; radio frequency; specific absorption rate; Biological system modeling; Finite difference methods; Guidelines; Humans; Intestines; Radiation safety; Radio frequency; Safety devices; Specific absorption rate; Time domain analysis; Biological effects; finite-difference time-domain (FDTD); radiation intensity; specific absorption rate;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2009.2024459