Noncontact ECG Measuring System Based on Capacitive PCB Electrodes

Traditional ECG sensors require good physical contact with skin, which have the following disadvantages, tedious preparation, incapability of long-term measurement, corrosion harm to skin, etc. This paper presents a novel gel-free, noncontact ECG sensor with a capacitive coppery coupling electrode inside coupling ECG from skin while an active shielding electrode surrounds the coupling electrode in order to reduce external noise. Besides, the integrated signal process circuit consists of low noise amplifiers, 4th order active high pass, low pass, notch filters and right leg drive circuit. Experimental results show that the noncontact ECG measuring system presented can detect ECG through clothing clearly and steadily. Finally, the influence of electrode area and sensor-skin distance on measurement results has been studied in detail experimentally.