Computation of electromagnetic field propagation characteristics of a dipole antenna submerged in sea-water

There is an increasing interest in utilizing underwater electromagnetic signals for communication purposes in marine environment. Difficulties encountered in implementing high bandwidth underwater data communication system arise from high propagation loss. This loss can be reduced considerably by using partial air path between submerged transmitters and receivers. With a view to analyzing propagation of electromagnetic (EM) waves through water-air interface, efficient computational techniques have been employed in this paper to investigate EM fields at a point in air generated by a submerged dipole antenna. Specifically, the method of Tang [1], who solves the Maxwell equations by decomposing the fields into transverse electric (TE) and transverse magnetic(TM) modes in a stratified media, have been utilized here. The electromagnetic field strengths are dependent on dipole moment, its placement in the stratified media, and electric and magnetic properties of the medium. A three-layer stratified media has been employed in this paper to model the environment consisting of atmosphere, sea-water, and sea floor. A concise description of the mathematical model describing the EM fields along with solution technique is presented in this paper. Parametric computational investigations are also presented to delineate effects of (i) multi-layer geometry, (ii) the electric and magnetic properties of the media, and (iii) orientation of dipole antenna, on EM fields at a specified observation point.