Magnetic field strength below a horizontal magnetic dipole located at the earth or ocean surface

A radiating loop antenna located at the earth or ocean surface produces a magnetic field within the conductive medium. The strength of this field is normally expressed by a set of integral equations for which there are no known solutions. The author develops approximations within the integrand that allow a closed form solution to be found for all points directly below the antenna. This accurate solution is valid for all combinations of frequencies and ranges at which practical communications between surface and submerged locations are possible.