Electric-Field Intrabody Communication Channel Modeling With Finite-Element Method

Abstract

Electric-field intrabody communication (EF-IBC) is a promising new scheme for the data exchange among wearable biomedical sensors. It uses the body as the signal transmission media. Compared with existing body area network (BAN) schemes, EF-IBC can achieve higher data rate with less transmission power. Until now, the detailed EF-IBC channel mechanism is not well understood. In this work, finite-element method (FEM) is utilized for the first time to investigate the EF-IBC channel. A circuit-coupled FEM model is established for the EF-IBC channel. The FEM model is extensively verified by experimental measurements. The new physical model enables the revelation of characteristics and effects of different components in the EF-IBC channel. The FEM investigation finds that the capacitive return path is critical to the characteristics of the EF-IBC channel. Parameters of the capacitive return path are quantitatively measured. The investigation also finds that the body plays an important role to the return path capacitance. The forward body path can be well modeled by a cascade of π-shaped circuits. Based on the FEM model of the EF-IBC channel, a simplified circuit model is derived to provide an efficient tool for the transceiver design.

Modeling and Characterization of the Implant Intra-Body Communication Based on Capacitive Coupling Using a Transfer Function Method

“…The electrical model of each unit block can be represented as an impedance Z , which is equivalent to the parallel connection of corresponding capacitance C and resistance R [2,18], as shown in Equation (1): $Z=\frac{1}{1/R+j\omega C}$…”

“…Due to the fact that the two coupling electrodes of the transmitter contact with the body directly, a primary current flow between the coupler electrodes is established and only a small secondary current propagates into the conductive body parts [5]. As a result, the body effectively shorts the signal from the transmitter, which increases the signal attenuation and the power consumption, and greatly shortens the operation time of the implant [18,19]; (2) The lack of a corresponding mathematical model. As for the research of implant IBC, the corresponding mathematical model is very important for achieving the characteristics of implant IBC [16,20].…”

“…In the on-body IBC based on capacitive coupling, only the signal electrodes of the transmitter and receiver are attached to the body skin directly, while both the transmitting ground electrode and the receiving ground electrode remain floating [10,21,22]. As a result, this avoids the body shorting the signal from the transmitter and more signal energy can reach the receiver electrodes [18]. Therefore, a comparatively lower power consumption can be achieved.…”

Dynamic Propagation Channel Characterization and Modeling for Human Body Communication

“…The latter uses a single signal electrode for both the RX and the TX, and the ground (GND) electrodes are floating in the air. The signal forward path is established by capacitive coupling with the human body, and the signal return path is formed by coupling with the ambient environment [18,19]. In this way higher data rate and smaller size could be achieved.…”

“…In another side of the spectrum, the majority of published works for HBC have assumed that the body was motionless [15,18,19,32–36], which is not the case for real-world BSN/BAN. References [11,37] reported a preliminary investigation of a dynamic HBC channel, only limited data sets and simple movement scenarios were investigated, therefore conclusions were quite pre-mature.…”