Fully Integrated Energy Harvesting Circuit With −25-dBm Sensitivity Using Transformer Matching

This brief presents a circuit to harvest energy from radio-frequency electromagnetic waves. It has a front-end transformer that simultaneously matches the harvesting circuit to a standard 50-Ω antenna and provides voltage gain, reducing the "dead-zone" of an 18-stage rectifier. The circuit is designed and prototyped in a standard 130-nm CMOS process with an active area of 200 × 250 μm 2 . Experimental results show a sensitivity of -25 dBm (-22 dBm without transformer) at 1.3 GHz.