Simulation analysis on the distributed capacitance of aircraft return conductor system

In the aircraft lightning indirect effects test, the lightning attachment points are represented by the current generator and return conductor attachments to the aircraft. The airframe and return conductors form a complex non-uniform multi-conductor transmission line. In order to analyze the distributed parameters of the coaxial return conductor system, the simplified model is built in the work to study the change rule of distributed capacitance with different return conductor arrangement. Besides, a lightning injection test model with the aircraft T50 is built, its distributed parameters are calculated by the electromagnetic simulation software FEKO, and then its characteristic impedances in different return conductor arrangements are determined. Thus, some useful rules are provided for characteristic impedance matching in aircraft lightning indirect effect test, and lay a foundation for further research on return conductor configuration.