Research On High-frequency Modeling Of Magnetic Beads And LNA Simulation Prediction Based On GA-DE Algorithm

Electromagnetic contamination of electrical and electronic equipment has been an important problem for many years.Ferrite magnetic bead as a passive filter is considered to be one of the most effective means to suppress radiation emission.It has the advantages of simple structure,small size and low design cost.Research on its high frequency model and non-ideal characteristics is of great significance to improve the application performance of magnetic bead in circuit simulation and solve electromagnetic compatibility more efficiently.This dissertation presents a method of high frequency modeling and simulation prediction of ferrite beads based on differential evolution algorithm.Firstly,the structure and main parameters of the magnetic beads were studied,and the magnetic beads were classified according to the functional and impedance characteristic curves,including general type magnetic beads,high-current type magnetic beads,sharp type magnetic beads,etc.Then,the application and mechanism of magnetic beads in EMC rectification projects are analyzed,including the suppression of radiated EMI and the solution of electrostatic discharge problems,etc.,and the magnetic beads are compared with other EMC passive filter parts to provide a theoretical basis for EMC rectification projects.Secondly,the high frequency equivalent circuit of the universal magnetic bead is studied in this dissertation.Parameters such as parasitic capacitance were introduced into the model to derive the expression of impedance.After the initial value of RCL was obtained by genetic algorithm,the parameters in the high-frequency model were fitted by differential evolution algorithm.Then the simulation results were compared with the measured results to verify the correctness of the model.Then,the influence of DC bias current on ferrite beads is studied,and the high-frequency circuit model of high-current magnetic beads is established.By designing T-bais to extract different dc bias magnetic beads shed electrical impedance method,large current type high frequency magnetic bead model is established,using MATLAB tool of magnetic beads circuit model of lumped components optimization values and dc bias current modeling,using the least squares polynomial regression analysis,through the measured results compared with the simulation results of the equivalent circuit model,validate the correctness of the model and accuracy,and error analysis.Finally,the application of magnetic beads in Low Noise Amplifier(LNA)and simulation prediction are studied.The LNA impedance network mismatch caused by magnetic beads was analyzed,and a typical LNA circuit was added with magnetic beads for simulation.The influence of magnetic beads on LNA circuit was analyzed by comparing the S parameters,so as to achieve the role of simulation prediction.