ELF Transfer Functions for a HED Source Propagating to an Underwater Receiver

Extremely low frequency radio waves are widely used for communication with underwater receivers because waves in this band can propagate with low loss in the earthionosphere waveguide and penetrate deep into seawater. In this paper, two transfer functions are presented to study the frequency response characteristics of the channel in this band. One is from a horizontal electric dipole source to the upper sea surface, and the other is from the upper sea surface to an underwater receiver. These studies are beneficial for designing communication systems.