面向人体通信的皮层脑电信号传输特性研究

随着人体通信的发展，对于人体脑电信号的研究和应用越来越广。现有研究局限于非侵入式脑电信号，对侵入式皮层脑电信号的研究较少。研究采用时域有限差分方法建立人体模型，探讨侵入式皮层脑电信号的传输特性。首先，分析10 MHz～10 GHz高频载波频段内不同接收电极间隔下信道传输增益的变化，确定皮层脑电信号最优载波传输频段。通过SAR量化分析人体吸收的电磁能量，评估模型的安全性。其次，研究发射器和接收器在不同距离下的路径损耗和阴影效应，建立了通信距离与路径损耗之间的二阶指数模型。结果表明，载波频段在约1 600 MHz左右，且接收器两电极间隔为10 mm时，信道传输增益达到最大值-45.63 dB。在信号传输过程中，通信距离和路径损耗之间遵循二阶指数模型关系，最终建立的路径损耗模型符合二阶指数分布，更能准确地描述信道的传输特性。

Research on the transmission characteristics of ECoG signal for human body communication

With the development of human body communication (HBC), the study and application of human electroencephalogram signals is becoming more and more extensive. Existing research is limited to non invasive electroencephalogram (EEG) signals and limited to invasive electrocorticography (ECoG) signals. In this study, a finite difference time domain (FDTD) approach was used to build a human model and explore the transmission properties of ECoG signals. First, the signal transmission that gain at different distances between the receiver electrodes were further analyzed in the frequency range 10 MHz to 10 GHz to determine the optimal transmission frequency band for ECoG signals. Quantitatively analyze the electromagnetic energy absorbed by the human body through specific absorption ratio (SAR) to evaluate the safety of the model. Secondly, we analyze the path loss of transceivers at different distances and show the second-order exponential decay relation between the distance and the path loss. Finally, the shadowing effect of the channel is investigated. It is shown that the channel transmission gain reaches its maximum -45.63 dB when the carrier frequency band is around 1 600 MHz and the distance between the two electrodes of the receiver is 10 mm. The resulting path loss model conforms to a second-order exponential distribution, which can more accurately describe the transmission properties of the channel.