Research Of The Complex Electromagnetic Environment Interpeering To The Coaxial Feeding Antenna System On The Warship Platform

Various antenna systems of cabins on the warship usually inevitablywork in a complex electromagnetic environment, including not only theradiation field of other antennas on the warship, but also the externalintentional or unintentional electromagnetic interference outside the warshipsystem. This interference will degrade the performance of equipments, andeven destroy the whole system. In recent years, many studies have beencarried out to investigate transient electromagnetic responses of cabinsystems illuminated by intentional electromagnetic pulses (EMP).Plentiful electromagnetic energy will couple into the feeding cable byantenna coupling when there are external electromagnetic pulses illuminatingthe system. Besides, windows, holes and slots are always needed forventilation, heat dissipation, connection with other equipments and so on,which will introduce direct coupling paths for external electromagnetic fieldpenetrating into cabins. Shielding layers are extensively used on the surfaceof the feeding cables in order to prevent electromagnetic interference.However, the outside electromagnetic interference energy can still coupleinto the inner core of cables, due to the limitation of cables' shieldingeffectiveness. So, electromagnetic field that coupled into the cabin bywindows and slots can further couple into the inner core of cables and comeinto introduction voltages and currents. A good understanding about theseEMI problems can help to do better electromagnetic compatibility (EMC)design and improve the performance of electrical systems. In this paper, Finite-difference time-domain (FDTD) method has beensuccessfully implemented for capturing cable-induced transient responses,together with the shielding effectiveness (SE) of cabins. Besides, antennacoupling FDTD model is presented in this paper, so as to improve theaccurateness and efficiency of the full wave simulation about feeding system.In general, our attention is focused on the following problems:1. Comparison of different thin-wire FDTD models;2. Different coaxial feeding monopole antenna FDTD models andantenna coupling model when the system is illuminated by externalelectromagnetic pulses;3. Analyze the impact factors of shielding effect (SE) of cabins, such asthe cabin shape, windows and slots orientation, the incident directionand polarization of EMP, antenna loaded and so on;4. Predict electromagnetic responses of a metallic conical frustum cabinor cubic cabin with one coaxial feeding monopole antenna, in thepresence of one or even more IEMP signals with high electric fieldstrengths so as to provide some important information for effectivelyevaluating complex electromagnetic environment effects (E3) oncertain communication platform.