Research Of Human Body Communication Based On Capacitive Coupling

In recent years, we have pay more attention to the development of portable wearable device, with portable wearable devices, it becomes more convenient for people to transmit and change information. Short-range communication is very important for the development of wearable devices,but existing short-range communication technologies,such as Bluetooth,Zigbee and WiFi, have some disadvantages that make wearable devices not easy to use. Human Body Communication is a new short-range communication technology which use human body itself as communication channel and it’s more suitable for wearable devices. Therefore,it’s necessary to do more research on Human Body Communication.Based on the analysis of human communication system signal coupling and the body antenna characteristics, this thesis determines the frequency range used by Human Body Communication. With Matlab modeler, simulation of electric field distribution on the human body is made.Based on result of simulation, this thesis analyses the electromagnetic characteristics of human body and body’s tissues channel model, and then calculates the electrical parameters of human tissue. Based on the research of body channel model, a distributed circuit model of human communication channel is established.To verify the simulation results, this thesis also sets up a measurement platform for human body communication and dos some research with different electrode, channel distance and different subject. The results shows that within the range of 1MHz to 100 MHz, the human body communication system behave a band pass characteristic, the pass band from 30 MHz to 60 MHz. The signal is transmitted mainly in the form of surface waves.Finally, a pseudo-random sequence generator based on FPGA is designed for the test of Human Body Communication system. The signal detected by oscilloscope is clear and doesn’t have time delay.