Design Considerations for Efficient Realization of Rectifiers in Micro-Scale Wirless Power Transfer Systems - A Review

To ensure optimal power transfer, a wireless power transfer system requires an efficient low-cost rectifier for realizing a self-powered wireless sensor node. This paper 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 ultra-low power application scenario of powering a wireless sensor node requiring several tens of μW power has been considered. The different passive rectifier topologies suited for low power applications have been designed and simulated using 0.18 μm standard CMOS technology. It is observed that, the auxiliary compensation technique exhibits a peak PCE of ~80%, and a peak PCE variation of ~0.7% and ~4% across different process corners and temperatures, respectively.