Design comparison of low-power rectifiers dedicated to RF energy harvesting

Radiofrequency (RF) energy harvesting is a key technique that can be employed in systems for generating some amount of electrical power to drive circuits in wireless communicating devices or, even so, to power supply a full node in wireless sensor networks (WSNs). This paper presents the comparison between two different CMOS rectifier topologies operating in the 900 MHz and 2.4 GHz ISM bands to convert RF power into DC power, both implemented in a CMOS 130nm technology. The first one is a traditional voltage multiplier today commonly used for scavenging energy from RF sources and for RFID applications. The second one is a cross-coupled voltage multiplier, which achieves a significant improvement in power efficiency and low voltage-drop compared with the traditional circuit.