Theory And Application Of Surface Waveguide Human Body Communication Modeling

Human Body Communication (HBC) is an emerging communication technology that uses human body as transmission channel. As an inevitable part of Pervasive Computing technology, HBC will be used widely in many application fields. In high speed communication application, surface waveguide HBC have extremely high performance and is becoming hot spot rapidly in relative research domains. But in the domain of surface waveguide research, there are also fundamental flaws like imprecise theoretical model and unclear transmission mechanism of signal. Also the achievements of HBC modeling research have not been used in the design and optimization of HBC equipment. To solve such problems, we take in-depth study on modeling theory and modeling application of HBC by direct and inverse analysis of electromagnetic problem.1) Analysis System of Surface Waveguide HBCTo analyze the modeling of Surface Waveguide HBC effectively, we propose an analysis system based on analytical method and numerical method of electromagnetic fields. The theory of waveguide on stratified media is chosen as analytical method, and the edge-based FEM and Galerkin weighted residual method are used as numerical method. The analysis system is the theory foundation and analysis method of this paper.2) Model of Surface Waveguide HBCTo solve the problem of imprecise theoretical model and unclear signal transmission mechanism in existing Surface Waveguide HBC research, a theoretical model based on stratified media cylinder is presented. A numerical model analyzed by Finite Element Method (FEM) is used for comparison and validating the theoretical model. Results of theoretical and numerical models shows that the new theoretical model proposed in this paper is superior to existing theoretical models in both calculation accuracy and prediction of trend, and is able to characterize accurate propagation mechanism of HBC signal. The propagation mechanism derived from the theoretical model is useful to provide design information for the transmitter and the modeling of the propagation channel in HBC.3) Research on the Simplification of HBC ModelIn the optimization of HBC equipment, theoretical and numerical model proposed in last part cost too much time and calculation resource. To solve this problem, we take a in-depth study in the calculation efficiency and simplification of HBC model, and propose a simplified numerical model of HBC. The calculation time of the simplified numerical model is just1/3of the complete numerical model, which keeps88%accuracy. The simplified numerical is very useful for fast evaluation of transmission mechanism of HBC signal and will be used for optimization of signal transmitter.4) Design and Inverse Optimization of Signal TransmitterThe existing signal transmitter of HBC is badly in integration of transmitter structure and efficiency and intensity of HBC signal. In prior studies, researchers often used direct analysis method of electromagnetic field, which did not achieve a good result. To solve those problems above, we introduce the inverse analysis into research of Surface Waveguide HBC. A new structure of signal transmitter is proposed to enhance the integration of transmitter, and the inverse optimization method based on NSGA-II algorithm is used to optimize the new structure of transmitter for efficiency and intensity. After optimization, the intensity and efficiency of new transmitter is much better than the existing transmitter.