Effect of electrode configuration on signal transmission through human body communication channel

 There could be two simple types of electrode configurations with respect to dominant electric field direction on the surface of human body channel:

One  type could be the coplanar capacitor formed by placing signal electrode adjacent to  ground  electrode or inter-digitated signal- and ground-fingers in the horizontal plane with the assumption of horizontal direction of electric field vector.

 The  second type could be the overlapping capacitive electrode formed by placing the signal  and  ground electrodes in the vertical plane. The direction of electric field intensity vector is  assumed vertical in this configuration.

 For  both configurations of electrodes, we are forming some kind of electrical dipole on the  surface  of human body. The electric field intensity has been calculated on the surface of  human body with finite permitivity and conductivity for the vertical infinitesimal electrical  dipole in [1]. However, it's also important to calculate electric field intensity for horizontal  dipole in order to compare the two coupling schemes and decide which one is better.

If  the human body acts as a waveguide medium as claimed in a european patent [2] then it's important  to see, for which component of electric field vector (horizontal or vertical) human body serves as a better medium. For example, it could be that human body attenuates one component of electric field say horizontal more than the other component of electric field say vertical. This would then define the better configuration of electrode for signal transmission on human body if we assume that the vertical component of the electric field is produced by the overlapping electrode configuration and the horizontal component of electric field is produced by the coplanar electrode configuration.

References

[1] J.Bae, H. Cho, K. Song, H. Lee, and H.-J.Yoo, “The Signal Transmission Mechanism on the Surface of Human Body for Body Channel Communication,” IEEE Trans. Microw. Theory Tech., vol. 60, No. 3, pp. 582-593, March 2012

[2] R. Bedini, A. Buratto, G. Casadio, G. Palagi and A. Ripoli, “Transmission system using the human body as waveguide,” European Patent EP0824889 A1, Feb 25, 1998.