Characterizing and Modelling Non-Linear Rectifiers for RF Energy Harvesting

AbstractRadio Frequency Energy Harvesting and power transfer, using rectifying antennas, are increasingly seen as an enabling technology of power-autonomous devices. The non-linearity of the rectification element, the diode, adds challenges when experimentally characterizing and comparing the performance of different rectifiers, requiring complex measurement techniques to characterize a diode experimentally, and adds to the challenges of designing a matching network. This paper presents a method for characterizing the power conversion of a mismatched rectifier using a single-port vector network analyzer, omitting the need for impedance tuners and accurately reflecting the non-linearity of the diode. The proposed approach minimizes uncertainty sources in the test setup and shows close agreement with optimized harmonic balance simulation. Finally, harmonic balance simulation is utilized to compare the source and load impedance of the two most common rectifier topologies, a single series and a voltage doubler, acting as a guide for matching network and antenna design.