Electromagnetic Field Estimations Considering of Implantable Cardiac Pacemaker EMI from Cellular Radios in Elevators
The purpose of this study is to estimate the Electromagnetic field (EMF) distributions emitted by cellular radios in environments surrounded by conductive surfaces, e.g., train carriages or elevators. In this paper, we discuss the effect of a passengers location on absorption of effectromagnetic fields inside the elevator in more detail. We proposed a numerical estimation method based on the FDTD technique to examine the EMF in actual elevators. Also an electric field histogram estimation method for effectric field strength was developed to deal with the complicated EMF distributions. This made it possible to estimate the EMI risk to pacemakers by cellular radio transmission quantitatively. As a result, we stated that the effects of losses due to the human body could not be disregarded for the estimation in the actual environment. As an example, we use a case in which one cellular radio user and one non-user are present in the elevator. An elevator having a PEC body was used and the FDTD model is shown in Figure 1.The homogeneous human phantom models are applied in the analysis. They have realistic shapes and homogeneous effectric parameters. We use a half-wavelength dipole antenna to represent a cellular radio operating in the 800MHz band. The antenna is set 20mm from the human phantoms head and 158 cm from the floor. In Figure 1, there are 2 phantom models with only one mobile radio operation. We consider the case in the varying location of the non-user phantom. Field histograms are used to estimate the percentage of areas having the same field strength in the inside plane of the elevator. Figure 2 shows the results of each of these scenarios. Here, the relative field strength normalized to a certain reference level determined from the experimentally obtained maximum interference distance of implantable cardiac pacemakers was used. We can determine whether or not a pacemaker malfunction is likely to occur by identifying those areas where the EMF exceeds that reference value. The results in Figure 2 suggest that the differences in the histogram due to the location of the non-user are small. Additionally, there are no results in which the maximum EMF strength exceeded the threshold limit which can adversely affect pacemaker operation. Further investigations for generalization about the effect of EMF absorption due to passengers in elevators are being conducted.
Y. Abiko L. Harris T. Hikage T. Nojima A. Simba S. Watanabe T. Shinozuka
Hokkaido University, Japan National Institute of Information and Communications Technology, Japan
国际会议
Progress in Electromagnetics Research Symposium 2007(2007年电磁学研究新进展学术研讨会)(PIERS 2007)
北京
英文
100
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）