| Electromagnetic energy harvesting technology converts the electromagnetic signals distributed in the surrounding environment into electrical energy,which can be used for the purpose of autonomous power supply or battery life for low-power electronic devices.The electromagnetic signals distributed in the environment with the advantages of sustainability and wide distribution,contributing to the wide application prospects and development space of electromagnetic energy harvesting technology.This paper analyzes the current situation of each module of the electromagnetic energy harvesting system in detail.Two matching rectifiers are designed for the rectifier module,and analyze the influence of the multi-tone signal on the performance of the system.The main research contents and achievements of this article are as follows:(1)Three rectifier circuits,namely,series,shunt,and single-stage voltage doubler,were built based on Schottky diodes.The influence of load and input power on conversion efficiency was studied,and single-stage voltage doubler achieves the best performance in the situation of the low input power.In order to improve the conversion efficiency of the rectifier,the matching network design and manufacturing of the rectifier were performed for 1.8 to 2.2 GHz in mobile communication and 2.4 GHz in WiFi.The measured results show that when the input power is at-20 dBm,the matching efficiency of the matched rectifier is about 6%,and the measured voltage is about 5.5mV;when the input power is at-10 dBm,the conversion efficiency is about 21%,and the measured voltage is about 48mV;and when the input power is at 0dBm,the conversion efficiency is about 43%,and the measured voltage is about 358 mV.(2)The influence of multi-tone signal on the performance of matching rectifier was studied from three aspects: the number of sinusoidal signals,the phase difference between signals,and the frequency spacing between signals.First of all,simulation and analysis was performed on the difference in the number of sinusoidal signals at the same frequency and different frequencies.It shows that the conversion efficiency of the matching rectifier increases by about 10% with the increase in the number of the sine signal at the same frequency;the conversion efficiency of the matching rectifier decreases by about 7% with increasing number of the sine signal at different frequencies.Secondly,the phase difference of the sine signal at the same frequency and different frequencies was simulated and analyzed,and it is concluded that the phase difference of the signals under the sine signal of at the same frequency has great influence on the performance of the rectifier,while the sine signal with the changes of the phase difference at different frequencies has little effect on the performance of the rectifier.Finally,the simulation analysis of the frequency interval between two sinusoidal signals shows that the performance of the rectifier decreases slowly when the frequency interval exceeds a certain frequency.(3)For the first time,a research on the mobile communication signal was proposed and its performance on the matching rectifier was analyzed.At first,the GSM signal,WCDMA signal and CDMA2000 signal of the mobile communication were simulated,and the best performance is achieved by CDMA2000 signal rectifier under the low input power.Then with the comparison and analysis between WCDMA signal,CDMA2000 signal and CW signal,it is concluded that the main factors affecting the performance of the rectifier are peak-to-average ratio,symbol rate and signal bandwidth,and so on.At the input power of-10 dBm,the conversion efficiency of CDMA2000 signal,CW signal and WCDMA signal are respectively 37%,31% and 24%,and the output voltage is 518 mV,362mV and 229 mV respectively. |
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