Reserch On RF Power Harvesting System Based On Metameterial Antenna

In order to solve the problem of power supply,a radio frequency energy harvesting node using an energy collection antenna based on metamaterial,which provides energy to WSN nodes in a wireless way is proposed in this thesis.Firstly,the electromagnetic energy in the environment is collected by the antenna and converted into AC electric energy.Then,the AC electric energy is converted into DC electric energy through rectification and other steps,and stored for the application use.To verify the validity of the method propos in this paper,the antenna and the energy collecting circuit are analyzed theoretically,simulated,manufactured and tested.In the aspect of antenna,the Fabry-Perot resonator model is applied to the antenna,and a metamaterial antenna based on FSS and EBG materials is proposed.In this paper,the principle of Fabry-Perot resonator is explained,and metamaterials of FSS and EBG are introduced.A metamaterial antenna based on a microstrip antenna with FSS material as the covering layer and EBG material as the bottom plate is designed with the assistance of HFSS.The simulation results show that the gain of a common microstrip antenna is improved obviously af'ter the metamaterial layers are loaded to the antenna.Performance of the fabricated antenna is tested.The gain of the antenna is improved by 4.3 1dB to 6.77dB and the efficiency of the antenna is 71.2%.In terms of energy collection circuit,firstly,three kinds of rectifiers are simulated with ADS.The simulation results show that the third-order charge pump performs better than the two other structures.So it is selected as the rectifier circuit used in this design.Performance of the fabricated circuit is also measured.The best load of the rectifer is measured as 10k? and the efficiency is 7.6%when the input power is-10dBm and the total efficiency of the whole circuit is 6.1%.The test result shows the usability.