Design Considerations for Efficient Realization of Rectifiers in Microscale Wireless Power Transfer Systems: A Review

To ensure optimal power transfer, a wireless power transfer (WPT) system requires an efficient low-cost rectifier for realizing a self-powered wireless sensor node (WSN). This article presents a comprehensive study and analysis of the various rectifier topologies and the accompanying circuit techniques available in the literature to achieve a higher power conversion efficiency (PCE). Based on the circuit topology employed, they are classified into different categories and compared accordingly. For a fair comparison, an ultralow power application scenario of powering a WSN requiring several tens of mu W power has been considered. The different passive rectifier topologies suited for low-power applications have been designed and simulated using 0.18 mu m standard CMOS technology. It is observed that the auxiliary compensation technique exhibits a peak PCE of similar to 80%, and a peak PCE variation of similar to 0.7% and similar to 4% across different process corners and temperatures, respectively.