Evaluation of the received signal level in relation to the size and carrier frequencies of the wearable device using human body as a transmission channel

Studies of wearable computers have attracted public attention these days. One of the area of interest is the communication system adopted in those wearable computers. As an example, wearable devices which use the human body as a transmission channel have been developed. When a user wearing the transmitter touches the electrode of the receiver, a transmission channel is formed within the human body. In this paper, investigations of the received signal level in relation with the carrier frequency and the size of the transmitter using human body as a transmission channel have been presented. The results show that the received signal voltage is slightly influenced by using higher frequency from 10 MHz to 100 MHz in the ISM frequency bands. However, it strongly depends on the size of the transmitter. In addition, it is necessary that the direction of the electrode of the transmitter is transverse for higher received signal level, compared with the longitudinal direction.