Human body communication in vehicle - Transmission characteristics between the forearm and the steering wheel

This paper proposed an in-vehicle application of human body communication as a form of communication technology that allows stable and low-energy communication within the vehicle. We investigated the transmission characteristics and electric field distribution between a wearable device attached to the driver´s forearm and a transmitter mounted on the steering wheel. It was found that at a distance of 130-190 mm between the wearable transmitter and the receiving electrode installed on the surface of the steering wheel, good transmission characteristics, S₂₁ = -27.8 to -31.3 dB, were observed. Furthermore, the greater the transmission distance, the more the transmission characteristics deteriorated. With regard to the electric field distribution, the results indicated that even within the motor vehicle, electric field distribution from near the wearable transmitter to the area around the human body is strong, yielding good transmission characteristics.