Computational investigation of electromagnetic fields in the atmosphere due to electric and magnetic dipoles placed in seawater

Electromagnetic (EM) fields at a point in space generated by electric/magnetic dipole embedded in a general anisotropic stratified media can be analytically solved [1] by decomposing the fields into transverse electric (TE) and transverse magnetic(TM) modes. The electromagnetic field strengths are dependent on the nature (electric or magnetic) of dipoles, their placement in the stratified media, and relative location of dipoles. A three-layer stratified media has been employed in this paper to model the environment consisting of air, seawater, seabed. The mathematical formulations provided by Tang [1] are used for EM field calculation containing both magnitude and phase information of Ẽ and H̃ fields for dipole antenna of 4 types namely: horizontal magnetic dipole along x- direction (HMDx), horizontal electric dipole along x- direction (HEDx), vertical magnetic dipole (VMD) and vertical electric dipole (VED). Parametric computational investigations are presented to delineate effects of i) the electric and magnetic properties of the media, ii) the nature and orientations of dipole sources, on EM fields at a specified observation point. It is observed that contributions from horizontal electric dipoles have comparable electric and magnetic field strengths at an observation point in the air.