Electromagnetic coupling analysis on coaxial cable of aircraft fuel measurement system

A numerical analysis method is presented for electromagnetic coupling problem in cables of aircraft fuel measurement system (AFMS). The reflection superimposition model of electromagnetic source is derived, then combined with transmission line (TL) equations and finite-difference-time-domain (FDTD) method, the hybrid FDTD method is improved. First, the electromagnetic environment of AFMS is analyzed, considering the actual geometric dimension of wing and characteristic electromagnetic source in AFMS. Then the coaxial cable is divided into external coupling system and internal coupling system, transmission line equations are used to model the above two systems, and the excitation fields are equivalent to distribution sources. Finally, the transient response on cable is obtained by TL equations with FDTD method. The numerical analysis result of reflection superimposition model is discussed in the given example. The influences of different reflection times are considered and it shows that the reflection superimposition model is stable and corresponded to actual response of practical problems.