MODÉLISATION D'ANTENNES TRÈS BASSES FRÉQUENCES (VLF/LF) : étude de l'influence de la structure, des composants associés et de l'environnement en vue de leur optimisation

摘要

Communications with Low Frequencies (LF) and Very low frequencies (VLF) are used for military purposes, specially for communicating worldwide with submarines underwater at shallow depths. The modeling and simulation of such antennas require numerical methods close to their validity limits. The subject of this thesis deals with the global modelization of VLF/LF [3-300 kHz] antenna structure taking into account the local environment such as : insulators, ground plane, buildings,... The first part of the thesis is devoted to the characterization of insulators. The behavior of these devices subjected to high voltages being unknown in the VLF/LF. A second part is devoted to the developpment of a “Thin Wire” model arbitrarily oriented integrating localized components. Three methods are presented and validated by comparison with theorical results. Finally, simulations of VLF antennas taking into account the numerous radiating arbitrarily oriented wires with surrounding insulators are presented.