Research On Flowable Design Method Of Bulk Current Injection Probe Based On Full-wave Electromagnetic Field Simulation

As the key instrument in bulk current injection test system,the injection current probe has a significant impact on its final tets results.In order to standardize the design process of injection current probe and optimize the performance of current probe,flowable design method of injection current probe is discussed in this paper.First of all,the basic theory of the current injection probe is analyzed in this papr.The relevant analysis shows that the current injection probe and the cable of the device under test form a transformer.An equivalent circuit model of the injection current probe and its calibration fixture is established,and the circuit model is used to analyze the influence of various parameters on the insertion loss of the injection current probe.Due to the particularity of the actual structure of the magnetic core inside the probe,the derivation process of the magnetic permeability of the open-air gap magnetic core is give in this paper.Then the simulation model of the current injection probe and its fixture is established in a simulation software,the electromagnetic parameters of the magnetic core in the simulation model are derived based on the actual measurement of the complete magnetic core.The correctness of the established simulation model and the modeling method of open-air gap magnetic core is verified by comparing the measured and simulation results of the standing wave ratio of the calibration fixture and the insertion loss of the injection current probe.On the basis of the above,flowable design method of injection current probe is proposed in this paper.That is,the design software of injection current probe is written by using the graphical user interface provided in MATLAB.This software based on the MATLAB-CST co-simulation technology can realize the functions of importing the target insertion loss of the injection current probe,establishing of magnetic core database,selecting suitable magnetic cores and optimizing some structural parameters of the probe.The insertion loss of the F-120-8 injection current probe by FCC is taken as the design goal in this paper,and the software is used to design probe.And the result shows that the combination of magnetic core and structural parameters selected by the software make the designed current probe meets the target requirement.