Geophysical subsurface probing with a horizontal magnetic dipole

The use of a horizontal magnetic dipole in geophysical subsurface probing with the electromagnetic fringes method is investigated. It is found that when placed on the surface of a half-space medium, angles of maximum power coupling into the medium occur at
\sin^{-1} ((1 + n^{2})/2n^{2})^{1/2}
in the endfire direction and
\sin^{-1} (1/n)
in the broadside direction, where
n
is the refractive index of the half-space medium. Also the broadside radiation pattern exhibits a sharper maximum as compared with that of a horizontal electric dipole, which provides a clearer indication of the depth of a subsurface layer.