The propagation and reception of transient electromagnetic signals in the presence of a conducting half-space
In this paper a theoretical treatment is given of the short-distance propagation and reception of a step-function in the presence of a conducting half-space. The step-function is generated by a horizontal electric dipole situated in the conducting half-space. First the waveforms of the electric and magnetic fields are computed for points in the conductor, making use of Laplace-transform theory. Since the vertical electrical field is discontinuous at the interface its waveform in points just above the conductor is derived separately. It appears that for horizontal distances larger than three times the antenna depth the attenuation of this vertical electric transient with distance is equal to that in the harmonic case, viz. proportional to the inverse square of distance. Moreover, smearing out of the signal as it is propagated in the horizontal direction does not occur, contrary to that of the other components. The waveforms of the vertical electric field and the component of the horizontal magnetic field parallel to the antenna are plotted.
Mijnarends, Peter E.