Effect of ground conductivity on the secondary field of a horizontal current-carrying loop

Abstract

The radiation field of a circular loop carrying an electric current and located horizontally above a lossy ground is formulated using the dyadic Green's functions. The resulting field vectors are then split into the primary and secondary components. The primary components represent those that would exist in the absence of the ground, leaving the secondary components to represent the contribution of the Earth. For different frequencies and various ground conductivities, the secondary components are determined and compared with the primary ones. The results indicate that in the vicinity of the loop, both within and outside the ground, the secondary fields are small at low frequencies and may be neglected. This provides a simplifying approximation to handle the return response of buried objects, excited by a circular loop located in the air.