A Comparative Study of the Electrodes Gels’ Electrical Properties in the Measurement Issues of Intrabody Communication

Abstract

Intrabody communication (IBC) technology is becoming progressively more standardized due to its low power consumption and high security features incorporated into the third physical layer of the IEEE 802.15.6 standard. Even then, there are still many challenges in normalizing the measurement issues of IBC. A major concern that should not be overlooked is the electrodes in the IBC, especially the popular use of gel electrodes. In the channel measurements, gel electrodes are commonly employed to improve the signal-to-noise ratio and prevent electrodes from falling off. In this paper, a comparative study of the electrical properties of gel was investigated during the measurement of human channel characteristics and to clarify the differences of them. Firstly, the basis of electrostatic field pole plate measurements and electromagnetic theory were introduced to interpretate how the relative permittivity and conductivity of different gels will influence the measurement results. Then the in vivo experiments with different gel or dry electrodes were performed to compare the differences induced by the gel. The results indicate that the influence of the gel on the human channel measurement is mainly concentrated below 400 kHz (the attenuation is reduced by 16.7 dB on average), and the stability of the permittivity and conductivity of the gel has a direct impact on the stability of its measurement of the human channel. This result may provide a meaningful reference for the standardization of electrode usage in IBC.

Keywords

intrabody communication / channel characteristic measurement / gel electrodes / permittivity / conductivity