Horizontal Wire Antenna Above Lossy Half-Space: Simple Accurate Image Solution

Abstract

A simple, approximate, but highly accurate, method is proposed for the analysis of horizontal thin‐wire antennas above a lossy half‐space. In the first step, the contribution of the lossy half‐space to the field of a horizontal Hertzian dipole above the interface, both in the half‐space above and in that below the interface, is approximated by the field of few (typically six) equivalent sources (images). The relative image intensities are obtained by enforcing the boundary conditions for the tangential components of the electric and magnetic field at a number of points at the interface. The field of the images is introduced into the Hallén equation; current distribution is approximated by polynomials and determined by point‐matching. The results for the impedance of horizontal dipoles obtained by the present method are in excellent agreement with the exact results (obtained from the Sommerfeld theory), although the proposed method is conceptually much simpler and requires at least an order of magnitude less computing time than the exact method.

Analysis of wire antenna structures above lossy homogeneous soil

“…This form has been applied in [21], [23]- [26]. In order to illustrate the range of validity of proposed approximations, the system of integral equations of Hallén's type is numerically solved using the point-matching method as in [4], [6], [7], [11]- [27], assuming the polynomial approximation (see [4]- [27]) for the current along the conductors of the observed antenna structure. …”

Arbitrary wire antenna above lossy half-space: rapid accurate image solution

“…The positions of images, as explicit functions of dipole height and relative complex permittivity of the lossy half-space, were given by appropriate formulas. 1,2 Some results of the performed numerical experiments (impedance of horizontal dipoles obtained with different number of image pairs) can be found in the previous paper. 2 However, to prove that the adopted images are also 'optimal' for wire antennas consisting of oblique segments, various antennas were analysed using different numbers of images.…”

“…1,2 Some results of the performed numerical experiments (impedance of horizontal dipoles obtained with different number of image pairs) can be found in the previous paper. 2 However, to prove that the adopted images are also 'optimal' for wire antennas consisting of oblique segments, various antennas were analysed using different numbers of images. As a typical example, Figure 2 shows the impedance of a small Yagi-Uda array inclined at an angle = 15°with respect to the ground plane, against the number of image pairs of a horizontal current element.…”

“…The basic idea of the proposed image method 1,2 was to approximate the reflected field of a vertical and horizontal Hertzian dipole (current element) by a field of a few elementary sources (images) situated below the interface and considered to be in a vacuum. These images are, in v. v. petrović and b. d. popović fact, approximately equivalent sources to currents induced in the lower half-space with respect to a restricted domain surrounding the dipole.…”

An Analytic Formula of the Current Distribution for the VLF Horizontal Wire Antenna Above Lossy Half-Space

“…The horizontal wire antenna located above the earth has been used widely in VLF electromagnetic system [1][2][3][4][5][6][7]. Compared to the vertical monopole antenna [8,9] which is typical of the most VLF transmitting antennas, the advantage of the horizontal antenna includes easy to be constructed and repaired, low cost, requiring no ground plane and so on.…”