The Effects of Electrode Configuration on Body Channel Communication Based on Analysis of Vertical and Horizontal Electric Dipoles

Abstract

The effects of electrode configuration on body channel communication (BCC) are studied for the development of body channel characteristics, such as frequency response, path loss, and resilience to other interferers. First, this paper introduces nine types of electrode configurations according to the arrangement and direction of both transmitting and receiving electrodes on the body. Each configuration is then modeled by means of vertical and horizontal electric dipoles. From Maxwell's equations, the complete equations of vertical and horizontal electric fields on the human body, followed by the ratios of the received electric field to the transmitted electric field, are obtained to find the theoretical body channel characteristics and the effect of electrode configurations on the body channel. The theory is verified with measurement results using a network analyzer and balun transformer. In addition to the channel characteristics, the influence of BCC and RF interference on the body channel is investigated and discussed along with receiving electrode configurations. Based on the measurement results, we found that vertical electrodes in the transmitter and horizontal electrodes with longitudinal direction in the receiver is the optimal configuration for BCC in regard to transmission gain, environmental sensitivity, and interference resilience. Finally, we suggest an effective parameter for BCC, which is equivalent reference distance to determine the proper electrode size for the required frequency response. The relation between the parameter and the electrode size is formulated for the purpose of proper electrode utilization in the design of BCC systems as well as in many potential applications.