Investigation Of The High Power Electromagnetic Pulse Coupling To The Cables On The Warship

Shielded cable is extensively used in communication network and communication system on board to avoid interference of outward electromagnetic pulse. However, in some cases such as HEMP,thunder environment or ultra-band electromagnetic pulse, these systems are inevitably impacted by high power pulse, which will induce some energy into the cable.This paper begins with the investigation of the coupling problem from external electromagnetic field to shielded cables. We divide this total system into two transmission line systems. The outer transmission line is composed of the shield of the cable and the ground while the inner transmission line is composed of the shield and the core wire of the cable. The two systems are connected by transfer impedance and transfer admittance of this cable, which reduces the computation complexity a lot. By using this method, we have computed the sheath current and internal current response of such a shielded cable under the influence of external transient electromagnetic field.For the following parts, we compute the voltage response of multi-conductor cable, cable networks and cascaded cable with numerical methods. The methods used in this paper including MoM (extract the parameters of the cable), FDTD (compute the voltage response of the multi-conductor cable) and Eigen Function expansion method combined with MoM (compute the electronic field at the junction). During these parts, we manly analyze the following problems:1. Extract cable parameters in three cases, especially considering the proximity effect and the inhomogeneous dielectric media case.2. Using FDTD, numerically computed the terminal voltage response in the three cases of multi-conductor cables while considering the conductor loss of the cable which is induced by the skin effect.3. Set up admittance matrix to obtain voltage response for different cable networks attached with different terminal impedance.4. Numerical investigation of the transmission characteristics of the cascaded cable. The results show that the more variation in radius between the adjacent connected cables, the more high modes will be induced and more resonance frequency will appear.