Capacitive Electrode for Bio-Medical Applications

Abstract

In recent years, advancements in medical and healthcare-based embedded systems have increased rapidly. Such systems include magnetic resonance imaging (MRI), computed tomography (CT) scanners, ultrasound imaging, digital flow sensors, electrocardiogram (ECG), and electroencephalogram (EEG) monitoring appliances. With the advancements in VLSI and e-technology, the overall chip size has reduced, and eventually, the functionality of the system has increased manifolds. In biomedical applications, electrodes are widely incorporated to sense the electrical activity of the human body. One of the vital use of the electrodes is to sense the ECG signal of the patient’s body for monitoring the activity of the heart. For this purpose, electrode equivalent model, electrode-skin interface, several different electrodes used in biomedical applications like surface electrodes, microelectrodes, needle electrodes have been studied. Apart from this Dry flexible electrodes using PDMS substrate and wet electrodes like Ag/Agcl electrodes are investigated, an effective capacitive electrode-based single-lead ECG system has been explored which contains pre-amplification circuitry, Band-pass filter, and notch filter. Each of these circuits is designed and the performance of an overall system is accessed using two different versions of theWilson central terminal ECG database. The proposed system has a very good correlation with the original ECG signal database. The frequency response of the band-pass filter and notch filter is computed and drawn to derive their cutoff frequencies. The presented capacitivebased electrode is proposed to be an optimal electrode for ECG signal detections in upcoming biomedical applications.