Analysis Of Influence Of Multisine Signal On Electromagnetic Energy Collection System

This paper designs an energy harvesting system capable of collecting radio frequency energy for mobile communication 3G,4G downlink band and 2.4 GHz WiFi.The main goal of this energy collection system is to convert the radio frequency energy of the designated frequency band into electrical energy and store it and supply it to low power device.The energy harvesting system consists of a low-pass filter,a rectifier,a DC filter,and a load and power management system.The power management system boosts the low voltage output of the rectifier circuit and stores the electrical energy in the energy storage container.A step impedance low-pass filter with a cut-off frequency of 2.7 GHz is designed in this paper.The rectifier circuit is analyzed with frequency of 2.4 GHz,and the single stage voltage doubler topology is used as the framework of rectifier circuit in this paper.The influence of capacitor,Schottky diode and load on the performance of rectifier is analyzed by simulation.After the impedance matching,the rectifier efficiency increased by 8.8 percentage points,the output voltage DC component increased by 81.4%,and effectively inhibited the rectifier circuit harmonics wave component with the input power of 0 dBm compare to original rectifier.In the 2GHz to2.7GHz frequency range,the rectifier circuit measured voltage is between 300 mV to 400 mV with the 0 dBm input.Analysis the influence of the multisine signal which consists of a few mobile communication downstream frequency on rectifier with simulation for the first time.The single stage voltage doubler topology is used to analyze the influence of the frequency relationship and phase relationship between the components of the multisine signal and the number of multisine signal components on the performance of the rectifier.The simulation results show that when the number of the same frequency signal gets larger,the higher the rectifier circuit output voltage will be;When the number of different frequency signals gets larger,the lower the rectifier circuit output voltage will be;what's more,when the phase interval of multisine signal components gets smaller,the rectifier circuit output voltage will get larger.A power management system is designed based on the LTC3108 chip,which uses a super capacitor as an energy storage component.The rectifier and power management system is cascaded measured with the-10 dBm power source,the super capacitor of the power management system output can collect 1.8V of electric energy.