Design Of Rf Energy Harvesting System For Low-power

This thesis focuses on the technology of RF energy harvesting for low-power wireless environment, which consists of antenna module, rectifier module, power management module and storage module. The design of each module is determined based on the status of research at home and abroad. Antenna module is achieved by using a patch antenna array with the parallel feed network. Rectifier module is designed by using a single stage voltage doubler rectifier. Power management module includes a DC-DC step-up coverter and a power management chip. Storage module is designed by using Super-capacitors.An array of rectangular microstrip patch antenna with 16 elements is developed and tested by adjusting element spacing and optimizing feed network. The measured gain reaches 20.3dBi and VSWR is less than 1.28.Through analyzing the characteristics of the Schottky diode, rectifier topology and diode selection, three models of rectifier circuit are built. The researches show the influence of input impedance, input power, capacitance and load on conversion efficiency performance. The rectifier circuit is developed by optimizing loads, matching and improved topology, which achieves conversion efficiency from 0.5% to 50% at low input power.The power management technology of LTC3108 with self-resonant DC-DC transformer is proposed. The circuit is developed by designing PCB layout, processing, welding and commissioning. The input voltage/output voltage curves of experimental measurement indicate that the circuit can work correctly and produce a voltage from 1V to 3.27 V when input voltage is in the range of 10 mV to 30 mV. Furthermore, the constant output voltage of 3.27 V is achieved when the input voltage exceeds 30 mV. The result greatly improves engineering utilization of low-power RF energy harvesting system.