MEMS based wireless energy harvesting mechanism for ECG and BCG application

The paper presents the novel concept of a low frequency, wireless energy harvesting system capable of acquiring, processing, and transmitting electrocardiogram (ECG) and Ballistocardiogram (BCG) data. The System on Chip (SoC) is designed to be capable of autonomous power management and operation derived from harvested power. A MEMS based piezoelectric energy harvesting cantilever is employed for this purpose. It consists of a silicon beam integrated with piezoelectric thin film (PZT) elements fabricated on parallel top. A silicon proof mass is attached to the silicon beam. The arrangement of silicon beam and proof mass enables the structure to extract energy from low frequency vibrations. The energy harvester when integrated with the proposed system can perform ECG heart rate extraction and atrial fibrillation detection while only consuming a few μWs of harvested power. This novel design of energy harvesters provides an additional benefit of Ballistocardiogram (BCG) that can help in early stages of a heart disease diagnostics.