Image Theory EM Fields of Horizontal Dipole Antennas in Presence of Conducting Half-Space

摘要

It is the purpose of this report to extend the use of quasi-static range finitely conducting earth-image theory techniques to the nearfield and farfield ranges. Simple engineering expressions for horizontal electric and magnetic dipole antennas have been derived for the air-to-air, subsurface-to-air, air-to-subsurface, and subsurface-to-subsurface propagation cases. These expressions have been compared with previously derived analytical (or numerical integration) results. For the air-to-air propagation case, the image-theory expressions are valid from the quasi-static to the farfield ranges, as long as the square of the index of refraction is large and the Sommerfeld numerical distance is small. For the subsurface-to-air, air-to-subsurface, and subsurface-to-subsurface propagation cases, the additional restriction that the measurement distance be greater than three times the burial depth of the source and/or receiver must be met. (Author)