Abstract: Implantable communication system is an important component of Body Area Network （BAN）, and it has bright prospects, especially in medical monitoring, disease diagnosis and assistive technology for persons with disability. In this paper, a multi-layer heterogeneous medium model of human tissue is developed by using Finite Difference Time Domain （FDTD） theory. And then, by means of implanted different channel on-and in body tissue, the research of the characteristic of implantable Human Body Communication （HBC）. Firstly, the human body model of multi-layer is founded, then considering that dielectric properties of human tissue are depend on frequency. In order to solve the problem of α, β and γ dispersion, the complex relative permittivity of the human tissue should be approximated by the Debye model. Secondly, the four different channels of on-body to on-body, on-body to in-body, in-body to on-body and in-body to in-body is investigated through simulation in HBC link. Furthermore, the propagation characteristics of HBC channels in rang of 0.3 MHz to 100 MHz are analyzed. Finally, the communication channel implanted experiment proves the feasibility of the inhomogeneous multi-layered model. Based on the analysis on the characteristic of implantable communication propagation, it is concluded that the channel path-loss is related with the distance and high pass property. The in vivo communication channel have more advantage into the HBC mechanism.

Key words: human body communication, finite-difference time-domain, multi-layer body structure, implantable communication channel

摘要： 植入式通信系统是人体体域网（BAN）的重要组成部分，在医疗监测、疾病诊断治疗和残疾人辅助方面有重要的应用前景。基于时域有限差分的方法（FDTD）原理建立多层非均匀介质人体组织模型，通过在体表、体内植入不同方式信道，研究植入式人体通信信道传播特性。首先，建立多层非均匀介质人体组织模型，考虑到组织介电特性与频率有关，随频率呈α、β、γ色散，需对介质Debye模型进行非线性参数拟合；然后，在人体通信链路体表-体表、体表-体内、体内-体表和体内-体内植入四种信道，分析0.3~100 MHz频段人体通信信道的衰减特性；最后，通过信道植入实验（猪肉）验证了非均匀介质建模的可行性。分析植入式人体信道路径损耗特性：在植入信道传播特性方面，信道路径损耗与信道长度相关且随频率呈高通特性，在信道植入方式方面，体内信道较体表植入更具有优势。

关键词: 人体通信, 时域有限差分, 非均匀介质人体模型, 植入式信道