Temperature Induced Degradation of RF Energy Harvesters Efficiency: Experiments and Interpretation

The conversion efficiency of an RF energy harvester is studied at 868 MHz as a function of temperature on a printed circuit board charge-pump, based on off-the-shelf diodes and capacitors. Extensive experimental measurements are presented in the temperature range from 25°C to 85°C, showing that the harvested power may significantly degrade with T, in particular at the lower incident power regimes. It is shown that the rectifiers quality, and precisely the temperature dependent rectification ratio of silicon Schottky diodes commonly used for this application, has the strongest impact of the harvester performances.