Analysis of Schottky Multistage Voltage Doubler Rectifiers for RF Energy Harvesting Applications

Multistage Voltage Doubler Rectifiers (MVDR) are known to increase the level of the output DC voltage of a Rectifying Antenna (rectenna). However, the RF / DC conversion efficiency is very sensitive to the internal electrical characteristics of the used diode. This paper then proposes an analysis of the performance of an MVDR according to the features of the Schottky diode. A Rectenna Figure of Merit (RFoM), considering the DC output voltage as well as the RF / DC conversion efficiency, is defined to analyze MVDRs with up to ten stages. This analysis makes it possible to obtain that the most effective rectifier diode differs depending on the number of stages of the rectifier. More specifically, it is observed that, for two stages, the most efficient diode is the Schottky diode HSMS2820. For MVDR with more than five stages, the SMS 7630 diode is more suitable for low input power levels (less than 5 dBm). It is also observed that, for power levels higher than 5 dBm, the HSMS2850 diode offers the best compromise in terms of output DC voltage and conversion efficiency.