Wireless Power Transfer
Near-field communication (or NFC) is used for near-field inductive charging, mobile contactless payment, and RFIDs in ID cards. In this research, our focus is on far-field wireless power transfer for low-power applications such as Internet-of-Things (IoTs). The research is based on an RF-to-DC charge pump design and an ultra low power boost converter circuit. Industry standard circuit software, Advanced Design System (ADS) and EagleCAD layout software are used to simulate and layout the circuit. Prototypes are fabricated and populated and tested using vector network analyzers, spectrum analyzers, source meters, and power meters.
 H. Lee, R. Nadgauda, W. Thain and B. Diong, "1 GHz charge pump with ultra-low power boost converter for increased output voltage," 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, Boston, MA, 2018, pp. 2543-2544.
(left) Prototype of 2-stage charge pump
(right) Wireless testing setup using an RF source and directional antenna at transmitter and log periodic receive antenna connected to the 2-stage charge pump and ultra-low power boost converter. Output voltage of 4.2 volts was achieved at a distance of 5.5 meters at 0.5 W transmit power. Close to 8 meters was achieved at 1 W transmit power.