Design of an efficient 2.45 GHz RF rectifier for energy harvesting from low RF power density environment

This paper presents a 2.45 GHz rectifying system for RF energy harvesting from weak RF power density environments. The main problem of RF energy harvesting is that the RF power exists in low levels in free space. Moreover, the efficiency of the voltage doubler rectifier used for energy harvesting depends seriously on the RF input power level, as it is very low at the low input RF power levels. The idea behind the proposed rectifying system is that the RF power is collected from various sources at the same frequency and aggregated using an array of power combiners. The output of the power combiners array can be adjusted to satisfy the input RF power required for the voltage doubler rectifier to operate at its maximum efficiency. Firstly, the proposed rectifying system components are designed and tested separately, then, the overall system is constructed taking into the account the impedance matching between the different system components. The proposed rectifier is simulated using ADS software and the extracted results show good performance. The rectifier has achieved maximum power conversion efficiency of 74 ^% at RF input power of 3.5 dBm instead of 73% at RF input power of 9.5 dBm.