Energy-autonomous Bi-directional Wireless Power Transmission (WPT) and energy harvesting circuit

This work demonstrates a novel 2.45-GHz bi-directional circuit that can operate as both a wireless power transmitter and energy harvester. The circuit is based on a class-F oscillator/rectifier and is energy-autonomous since it does not need an external bias supply for either power transmission or power reception. Bi-directionality is exploited in two steps: the system first operates in rectifying mode with harvested DC voltages for biasing the oscillator; followed by the transmitting mode where the harvested DC power is used to start up oscillations. Conversion efficiencies for both configurations are higher than 50% for output/input RF power in the 10dBm range. This component can be exploited as a “power relay node” for distributed battery-less energy autonomous microsystems.