An effective FDTD scheme for the propagation of VLF-LF radiowaves in the Earth-Ionosphere waveguide

摘要

Very low frequency (VLF) and low frequency (LF) waves remain used to transmitting toward submarines because they can be received a few meters under the sea surface, a possibility not allowed by other frequency bands. To predict the propagation of such waves, the waveguide and wavehop methods have been developed during years 1960–1980. Both are effective in terms of computational cost, but have some drawbacks. During years 1990–2000, a third method was introduced to compute VLF-LF propagation, the finite-difference time-domain (FDTD) method (Thévenot et al, Annales des Télécommunications, 1999). The price of the full wave method is a far larger computational time, but this is a drawback increasingly small as the computers become increasingly powerful.