Fields of a horizontal loop of arbitrary shape buried in a two‐layer earth

Expressions have been derived for the magnetic field in air produced by a buried horizontal loop of arbitrary shape. Numerical results are presented for both circular and rectangular loops. Rectangular loops produce an azimuthal magnetic field component which is not present in the case of a circular loop. The results have application to source location in mine rescue techniques. In such cases, frequencies in the audio range are employed, and the assumption of a uniform current in the source loop is well justified.