Research On Field-line-Circuit Hybrid Time Domain Simulation Method For RF Rectifier Antenna

In recent years,with the rapid development of wireless communication technology,with the extensive use of this technology in aerospace,medical and other fields,how to continuously supply wireless electronic devices has become one of the most popular research directions.As a key part of the energy harvesting system in Wireless Power Transmission(WPT),RF rectification antennas can convert microwave energy into electrical energy in the environment and ultimately power wireless electronic devices.Therefore,the RF rectification antenna system has become a key research content in wireless energy transmission technology.This paper takes the complex wireless power transmission technology as the research background,and mainly study the antenna rectification structure including transmission line.By using Right Hand Grip Rule,,the three-dimensional field information can be converted into a current source,and then the actual rectifying antenna system constructed by connecting with the transmission line network circuit is used to analyze the variation law of the transient voltage and current of the transmission line terminal.Because the actual rectifying antenna system is more complicated,the research content of this paper is mainly as follows: Firstly,electromagnetic analysis and modeling based on the actual physical situation is proposed,including receiving antenna and transmission line.In this paper,the full-wave FDTD method is used to obtain the spatial electromagnetic field distribution including the induced voltage of the receiving antenna.By using Ampere's law,the three-dimensional field information can be converted into a current source.The induced voltage will then be used as a source in the rectifier circuit simulation,set as a mandatory term in the telegraph equation of the transmission line network.Since the terminal of the transmission line is usually a rectifying circuit structure inside the actual antenna rectification system,the rectifying circuit is a non-linear load or even a complex circuit network containing various active devices,and the transmission line is often non-uniform.The second part is mainly for dealing with non-uniform transmission line termination nonlinear load conditions.At this time,it cannot be solved linearly.It is necessary to modify the FDTD iteration equation at the transmission line and the load port to match the update equation of the transmission line.The specific process is to first equilibrate the circuit model with a complex transmission line network that terminates the nonlinear load,and then introduce the MNA(Improved Node Method)to solve the equivalent model.Finally,the obtained transient voltage and current are compared with the commercial software HSPICE simulation results to achieve consistency.In the third part,the field-line-channel cooperative simulation method between the transmission line and the terminal circuit of the system is studied by studying the signal received by the patch antenna.This method mainly includes modified three-dimensional full-wave electromagnetic simulation,one-dimensional transmission line FDTD method,Kirchhoff's law and improved node method to solve the nonlinear circuit of transmission line terminal.The numerical results show that the hybrid finite difference time domain(FDTD)method proposed in this paper is compared with the HSPICE method.This method has good accuracy and has been successfully applied to the rectenna system.