Quasi-static fields of dipole antennas located above the earth's surface

摘要

The electric and magnetic field components produced by vertical and horizontal dipole antennas (both electric and magnetic types) located at or above the surface of a semi-infinite conducting medium are derived and presented for the quasi-static range. The horizontal separation between the transmitting and receiving dipole antennas (ρ) is assumed to be much greater than their heights (h and z, respectively). These derivations are the result of applying the quasi-static approximation to the basic Sommerfeld integrals, utilizing the reciprocity theorem and expanding the exponential term involving the antenna heights in a power series. When ρ is much greater than an earth skin depth (δ), ρ ≪ δ, or h = z = o+, the formulas for the field-component expressions reduce to previously derived results. Some numerical values for these expressions are also provided.