Research On Low Level Equivalence Mechanism And Test Method For Ridiation Sensitivity Of Hirf

With the increasing number and complex of electronic circuits on aircraft,it is necessary to test the electromagnetic radiation of aircraft.As an alternative to full-level irradiation test,Low Level Couple(LLC)has the characteristics of low cost and high feasibility.Therefore,LLC is used as the test method of HIRF radiation sensitivity test in relevant domestic and foreign standards.However,different standards have different provisions on LLC,and the description of this method in GJB 8848-2016,the only domestic standard containing LLC,is not detailed enough.Therefore,it is necessary to study the test method and equivalent mechanism of LLC.The influence of plane wave azimuth,polarization angle and impedance of the interconnected system on the terminal induction current is simulated and calculated by using transmission line theory and field-line coupling theory in MATLAB firstly.When the peak induced current of the cable appears is sorted out in list.Secondly,the influence of the direction of the electric field and the height and position of the cable on the terminal induced current is further simulated in CST when there are shells and openings.The results show that the test of transfer function can focus on the cases when the incident direction of plane wave is perpendicular to the plane of the gap and the electric field direction is parallel to the short edge of the slot.At the same time,when laying out the cable,keep it as far away from the gap as possible and reduce the height of the cable,thereby reducing the coupling current on the cable.For the equivalence of LLC,a simulation model is established to simulate BCI test in CST.The results show that the longer the cable is,the earlier the valley value of inductive current appears on the cable,and the more frequency of under-test may occur;the inductive current on the cable is closest to the calibration value when the electric field probe is placed 900 mm away from the device under test;the height of the cable and the position of the cable relative to the center of the probe have little influence on the inductive current and will not affect the test results.Then RS and BCI test were carried out in anechoic chamber,as the same time,the results show that the forward power selection of BCI in ISO-11452 is more reasonable.Finally,the automation test procedures of the LLSC transfer function measurement,current injection test and sensitive level determination test are written in software Labview.