Non-contact, capacitive biosensor electrodes for electrostatic charge reduction

Non-contact capacitive sensors are receiving much attention as the desire for long-term portable biological sensing devices grows. However, electrostatic discharge (ESD) generation, arising from the sensor electrodes rubbing against the subjects clothing, is a significant challenge. We propose an actively driven shielding electrode with a grid-multilayer structure. We have considered and compared five electrode prototype designs. The signal-to-ESD noise ratio (SENR) and maximum amplifier noise budget were measured for the purposes of comparing the different electrode designs. The results indicate that the grid electrode has relatively moderate SENR and an acceptable noise design budget better than the other proposed prototypes.