Subsurface communication between dipoles in general media

In his book, Dipole Radiation in the Presence of a Conducting Half-Space, Baños analyzes the problem of communicating between two points in the ocean by means of infinitesimal dipoles. His general formulas involve complex integrals which are reduced to simple approximate expressions in special cases that correspond to limited ranges of the numerous parameters. A numerical study of the general problem for antennas in seawater was made by Siegel and King and compared with Baños' special cases. In this paper the numerical approach is extended to other than conducting half-spaces. The three cylindrical components of the electric field of a horizontal electric dipole in seawater, lake water, and dry earth have been computed and intercompared as functions of the frequency and of the distance between the source and the receiver. The applicability of Baños' special formulas is examined. The results are discussed in their bearing on the design of directive systems for lateral-wave and direct transmission.