Wang Lujia, Liu Li, Hu Chao, Meng Max Q
Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
Annu Int Conf IEEE Eng Med Biol Soc. 2010;2010:654-7. doi: 10.1109/IEMBS.2010.5627228.
In order to accurately estimate (build) the radio signal propagation attenuation model, especially inside the gastro-intestine (GI) tract of the human body, the Radio Frequency (RF) absorption characterization in human body is investigated. This characterization provides a criterion to design the Received Signal Strength (RSS) based localization system for the objective inside the human body. In this paper, the Specific Absorption Rate (SAR), E-field, H-field of the near and far field are investigated at frequencies of 434MHz, 868MHz, 1.2GHz and 2.4GHz respectively. Then, the numerical electromagnetic analysis with the finite-differencetime-domain (FDTD) is applied to model the in vivo radio propagation channels by using a dipole antenna. Finally, simulation experiments are carried out in homogenous and heterogeneous mediums. The results show that the electromagnetic (EM) propagation is not only distance and orientation dependent, but also tissue absorption dependent in human body. The proposed model is in agreement with measurements in the simulation experiments.
为了准确估计（建立）无线电信号传播衰减模型，特别是在人体胃肠道（GI）内，对人体中的射频（RF）吸收特性进行了研究。这种特性为设计基于接收信号强度（RSS）的人体内部目标定位系统提供了一个标准。本文分别在434MHz、868MHz、1.2GHz和2.4GHz频率下研究了近场和远场的比吸收率（SAR）、电场（E场）和磁场（H场）。然后，应用时域有限差分（FDTD）数值电磁分析方法，利用偶极天线对体内无线电传播信道进行建模。最后，在均匀和非均匀介质中进行了仿真实验。结果表明，电磁（EM）传播不仅取决于距离和方向，还取决于人体组织的吸收。所提出的模型与仿真实验中的测量结果一致。
