An Efficient RF power harvester for low input power with reduced dead-zone

Radio frequency energy harvesting circuits have to harvest energy from very weak sources demanding high sensitivity and high efficiency. In this paper, an efficient RF energy harvester for wireless sensor networks is presented. The circuit is based on a multi-stage rectifier that exploit threshold self-compensation together with transistor gate and bulk stimulus. The input is matched to 50Ω through a matching network that provides voltage boosting to the rectifiers input terminal. According to the desired performance, a 910MHz harvester with matched input comprising a 10-Stage rectifier has been designed in an 130-nm CMOS process. Considering a -20dB input power signal the circuit can supply a 1MΩ load with 1V/1μW output voltage and power with an PCE of 10%. The circuit exhibits a maximum PCE of 27% at -16dBm with 0.8V/6.4μW output voltage and power. The achieved results exceed the performance of previous work in terms of energy efficiency at input power lower than -15dBm.