Research On The Performance Of Airborne Electronic Device In The Lightning Environment

With the rapid development of aircraft technology,more and more electronic equipment is used in aircraft avionics system,which increases the risk of external electromagnetic interference on the aircraft.The energy of lightning is huge and its spectrum is wide,so the electromagnetic interference generated by lightning is one of the biggest threats to the operation of electronic equipment in aircraft.As the aircraft lightning test is difficult to realize and very dangerous,it is significant to apply the simulation method to study the interference of lightning on the aircraft.In this thesis,the impact of lightning signal on the performance of electronic equipment in aircraft is simulated and analyzed,which provides the necessary data and theoretical support for the airborne electronic equipment lightning protection design.Firstly,the coupling effect of lightning electromagnetic pulse on aircraft cable is studied.The influence of different cable length,cable load impedance,cable distance from ground and cable type on the coupling of lightning electromagnetic pulse is analyzed concretely.According to the simulation results,the principles of aircraft cable selection are proposed to reduce the interference of lightning on aircraft.Secondly,the electromagnetic effect is simulated and analyzed when the plane is struck by lightning.The current on the surface of the aircraft and the voltage induced by the airborne cable are analyzed under different lightning current injection paths.Then the surface current of the aircraft and the distribution of electric field inside the cabin are studied under different skin materials.Finally,as one of the important element of the RF front-end of the airbome electronic equipment,the influence of lightning electromagnetic pulse on performance of low noise amplifier(LNA)is studied.Firstly,the shielding effectiveness of the metal cavity with heat dissipation and ventilation holes is studied,and the influence of the different opening shape and the number of openings on the shielding effectiveness is analyzed.Secondly,the design method of LNA is introduced.In the end,the influence of the lightning impulse on the gain and noise of the LNA is simulated,and the sensitive degree of the different pins is compared.According to the results of the simulation,corresponding protection programs of the active device on the aircraft against the lightning are proposed.