The Quasi-Near Fields of Dipole Antennas

Abstract

The electric- and magnetic-field components produced by vertical and horizontal dipole antennas (both electric and magnetic types) located over, on, or below the surface of a semi-infinite conducting medium are derived and presented for the quasi-near range. (The measurement distance is much greater than an earth skin depth, but much less than a free-space wavelength.) Previously derived results are briefly summarized. The horizontal separation p between the transmitting and the receiving dipole antennas is comparable to their heights. The derivations are the result of applying the quasi-near approximations to the basic Sommerfeld integrals and, in some cases, utilizing the reciprocity theorem. When p is much greater than the antenna heights, the formulas for the field-component expressions reduce to previously derived results. It is observed that some of the field-component expressions are characterized by unusual height gain (or loss) functions. Some numerical values for these functions are provided. © 1967, IEEE. All rights reserved.