A 5.8-GHz RF VCO-Based Sensing System with Integrated RF Energy Harvesting in CMOS 65-nm for Health Monitoring Applications.

Implanted devices are used for health monitoring systems and medical diagnoses. These devices demand long-time operation and small size. Based on that, an integrated ISM 5.8 GHz RF-powered sensing system is proposed in this work. It is designed in a CMOS 65 nm technology to work with a supply voltage of 1 V that is provided by an RF -energy harvesting circuit. A VCO-based analog-to-digital converter is implemented to convert analog input signals in the range of 0 V to 1 V with 8-bit resolution, and the digital information is transmitted by an OOK transmitter. The schematic-level simulation has shown that the circuit is able to operate as expected, presenting a total power dissipation of around 5 m Wand input sensitivity to proper energy harvesting of 9.6 dBm and transmitted power of -2.4 dBm.