Reconfigurable Multistage RF Rectifier Topology for 900 MHz ISM Energy-Harvesting Applications

Energy harvesting (EH) offers several benefits for integrating compact low-power wireless nodes into emerging microscale applications, such as the Internet of Things (IoT), wearable and implantable medical diagnosis, and so on. In this study, an optimum approach is developed to design an adaptive high-performance rectifier for EH wireless charging. The rectifier architecture is based on a simple voltage doubler configuration. The structure can be extended to achieve the desired output voltage level without altering the impedance matching network. The voltage doubler stage is duplicated symmetrically to increase the voltage to the desired levels. The matching circuit employs a simple L-network that consists of a series-inductive branch and a shunt LC branch. To verify the logical operation of this approach, two rectifier prototypes were developed, and the performance of each structure was separately evaluated and compared. The comparison shows good agreement between the simulation and measurement results of the two configurations. For example, the peak measured efficiency is 65% at an RF input power of 10 dBm, and the simulated value is 70% with a terminal load of 3.3 k Omega. The main objective of the proposed design is to enhance the output voltage without changing the matching network.