| For the electromagnetic wave energy harvesting technology that converts RF signals into DC energy in the environment,this paper analyzes its practical value and feasibility in detail.In the case of low-power input signals,it has a broader practical space.And it focuses on the implementation of electromagnetic wave energy harvesting technology and RF-DC rectifier circuit.It also analyzes the effects of modulated signals,communication signals and multi-frequency mixed signals on the energy harvesting system.The specific work of this paper is as follows:(1)From the practical point of view,the second-order voltage double circuit structure is determined.The RF-DC rectifier circuit with two center frequency of 1.9GHz and 2.4GHz is designed,and the sixth-order step impedance low pass filter working at 2.4GHz.The rectified efficiency of the matched design circuit is 59.8%,and the measured low-pass filter S11 is around-20 dB.In the condition of 0 dBm input signal power,the actual measurement results of the 2.4GHz rectifier circuit’s output voltage is 580 mV.(2)Sinusoidal signals for multi-frequency mixing are discussed from the perspective of signal spacing,signal bandwidth,and signal amplitude.Firstly,the influence of the interval of different signal center frequencies on the system is discussed.It is found that the performance of the signal interval is the best when the signal interval reaches a certain value.Secondly,the simulation of different bandwidth values of the signal is carried out,and system performance of the 8MHz bandwidth of 8-tone is best.And,when the number and bandwidth of different signal frequencies are appropriate can achieve best Power Conversion Ratio(PCE).Finally,under the premise of the same signal input power,the amplitude of the member signals is discussed from the same and different frequency of the member signals.When the power of the input signals is consistent and the amplitudes of all the members are the same,the system performance is the best.However,the difference in amplitude is not much different.Overall,the difference in amplitude has little effect on system performance.(3)The modulation signal and communication signal were studied,and the performance of the system under the same input power was discussed.Modeling simulations for 1-tone,2-tone,4-tone,8-tone,QPSK and GSM signals revealed that 8-tone signals have the best system performance for Multisine signals,its value of PAPR(Peak-to-Average-Power Ratio)is 12.13 dB and peak voltage is2.391 V.For QPSK,GSM signals and 8-tone signals,the PAPR values of the former two are 3.05 dBand 3.19 dB respectively.It is concluded that the greater the peak value of the signal at the same input power,the better the system performance.In the case of system input power is 0 dBm,the output voltages of the QPSK,GSM signals,and 8-tone signals are 1.449 V,1.491 V,and 2.391 V,respectively. |
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