A Mixed-Signal Chip-Based Configurable Coherent Photoacoustic-Radar Sensing Platform for In Vivo Temperature Monitoring and Vital Signs Detection.

For precise health status monitoring and disease diagnostics in the current COVID-19 pandemic, it is essential to detect various kinds of target signals robustly under high noise and strong interferences. Moreover, the health monitoring system is preferred to be realized in a small form factor for convenient mass deployments. A CMOS-integrated coherent sensing platform is proposed to achieve the goal, which synergetically leverages quadrature coherent photoacoustic (PA) detection and radar sensing for versatile healthcare. By utilizing configurable mixed-signal quadrature coherent PA detection, high sensitivity and enhanced specificity can be achieved. In-phase (I) and quadrature (Q) templates are specifically designed to accurately sense and precisely reconstruct the target PA signals coherently. By mixed-signal implementation leveraging an FPGA to generate template waveforms adaptively, accurate capturing and precise reconstruction on the target PA signal can be attained. The multiplication between the received PA signal and the templates is implemented efficiently in analog-domain by the Gilbert cell on-chip. In vivo temperature monitoring was realized based on the integrated PA sensing platform fabricated in 65-nm CMOS technology. With the help of an integrated radar sensor deployed in the indoor scenario, noncontact monitoring on respiration and heartbeat rates can be attained. By complementary usage of PA-EM sensing, comprehensive and cognitive health status monitoring and remote disease diagnostics can be achieved for the current global COVID-19 pandemic and the future pervasive healthcare in the Internet of Everything (IoE) era.