Research On Environmental Radio Wave Energy Harvesting System

With the rise of Internet of Things,the popula rity of wireless sensor network,and the upgrading of integrated circuit technology,low-power communication system will become the future development trend.Wireless sensor network will gradually develop to ultra-low power mode.The rapid development of wireless communication,radio waves become more and more abundant,and wireless sensor network through the radio waves in the environment self-powered will be possible.The two main parts of the radio wave energy harvesting system are the rectifier circuit and the receiving antenna.In order to realize the effective acquisition of radio wave energy,it is necessary to improve the receiving efficiency of the antenna and the rectification efficiency of the rectifier circuit to minimize the energy loss.Therefore,the performance of the receiving antenna and rectification efficiency is very important in the energy harvesting system.In this paper,in order to make full use of and receive d radio wave energy of the environment the broadband polarized waveguide dipole antenna and wideband rectangular patch circular polarized antenna are studied and designed.the dipole patch antenna used gradient structure,to achieve broadband resonance from 2.2 to 3.3GHz.Through the broadband rectangular patch antenna slotted and added auxiliary radiation patch,constituting the external field perturbation,in order to achieve the antenna's broadband circular polarization vary from 1.7 to 2.6GHz,the corresponding circular polarization frequency range from 1.8 to 2.4GHz.And the antenna was processed and tested.The main purpose of the rectifier circuit is to rectify the electromagnetic energy received by the antenna and convert the received RF energy into DC energy.So the design of the rectifier circuit will directly affect the DC output voltage and output efficiency.In this paper,getting through the analysis of the working principle of the diode rectifier circuit,select the suitable rectifier diode for RF energy harvest.Finally employ Schottky diode using double pressure rectifier structure,in the ADS harmonic balance s imulation,to achieve the RF into DC voltage Function.In order to realize the minimum energy loss of the rectification system and the maximum rectification efficiency,the design and analysis of the broadband impedance matching network for the antenna and the rectifier circuit are carried out.Through the design and optimization of the broadband impedance matching network,the layout and principle of the microstrip line achieve rectification efficiency from 23% to 42% with the 0d Bm input power conditions,range from 1.7 to 2.6GHz,the corresponding DC output voltage vary from 0.43 to 0.58 V.The broadband circular polarization antenna and rectifier circuit were proces sed and tested,and the resonance frequency of the broadband circular polarize d antenna was from 1.8 to 2.5GHz.The tested rectifier circuit in the 0d Bm input power conditions,from 1.7 to 2.6GHz achieved the DC output voltage vary from 0.12 to 0.25 V.This verifies the rectification effect of the whole system and realizes the purpose of broadband RF rectification from 1.7 to 2.6GHz under 0d Bm input power.