Co-Design of an Auxiliary Self-Bias Module and a CMOS Rectifier for RF Energy Harvesting

This brief presents a novel CMOS rectifier for ultra-high frequency (UHF) RF energy harvester, which achieves a high sensitivity. Compared to other state-of-the-art topologies, the proposed architecture uses an auxiliary self-bias circuit to change the direct-current (DC) bias voltage of transistors, thus improving the sensitivity of rectifier. Meanwhile, the circuit expands the range of high efficiency input power due to the rectifier has higher power conversion efficiency (PCE) under low input power. A six-stage rectifier driven by the auxiliary self-bias circuit is designed and fabricated in a standard 130nm CMOS process technology. Operating at 915MHz and driving a 25K
$\Omega $
load resistor, the measured PCE of this brief is 72.9% at −9.6dBm input power. A sensitivity of −26dBm is measured with 0.8V output voltage across a capacitive load.