Bioimpedance sensing in wearable systems: From hardware integration to model development

Wearable sensors for e-health applications are quickly moving from the research field to market. Bioimpedance has the potential for playing an important role in this scope, especially because of its relatively reliable, electrode based sensing principle and its broad range of applications. On the other hand, there are also some challenges for the successful exploitation of this technique in a wearable device, like the reduction of power consumption and the control and optimization of the measurement for a specific application using a wearable electrode setup, more compact than the ones commonly employed in literature. This work discusses these two aspects, summarizing the results obtained with a low power bioimpedance architecture embedded into a wearable patch, and presenting a 3D finite element model which is used to analyse and investigate the bioimpedance measurements obtained through the patch. A comparison with the traditional electrodes setup shows similarities and differences in terms of sensitivity to organs conductivity, and confirms the suitability of a bioimpedance sensor integrated into a wearable patch.