Calculated pattern of a vertical antenna with a finite radial‐wire ground system

Abstract

The appropriate form for the surface impedance of a radial-wire ground screen is utilized to obtain quantitative effects of the important parameters (number of radials, length of radials, wire radius, and ground constants) on the low-angle radiation of a vertical antenna. An approximate correction term is derived to account for currents reflected from the edge of the screen. The effect is small for large screens, but it may be important for smaller screens.

The effect of an imperfectly conducting plane upon an incident electromagnetic field

“…Other integral formulations exist [15], but the present approach has the advantage that the solution can be directly interpreted in terms of the radiation pattern. A numerical solution is developed for the case of a dipole over a finite ground screen and, consistent with the findings of [10] and [15], this is found to give a leading order far field that is in good agreement with that derived on the basis of the PO approximation. In the case of the second-order field, however, the more exact numerical solution shows the PO approach to be inaccurate.…”

Performance of Ground-Based High-Frequency Receiving Arrays with Electrically-Small Ground Planes

“…Wait et al published results for small radial-wire ground planes [3]; large radial-wire ground planes [13,17]; small disk ground planes [3]; large disk ground planes [6,17]; large ground screens [4,9,12,14]; nonhomogeneous Earth [5,7,8,10,11,15]; and assorted ground planes [16]. Rafuse and Ruze [18] published results for large ground screens and radially-nonhomogeneous Earth.…”

“…_ 8.0 wavenumbers and possibly larger radii. Accordingly, d CCIR (a) is better approximated by equation (2)(3) than by equation (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17); namely, Similarly, the peak intensity of the angular distribution of external noise is not significantly affected by the extent of the ground plane for a given external noise factor and shape of the angular distribution, provided that the external noise is angularly-distributed over a large solid angle. For example, the peak intensity of the angular distribution for electrically-small ground planes relative to that for a perfect ground plane will be unchanged for uniform external noise; increased by a factor of (2.6/1.805) = 1.44 = 1.6 dB for external noise with a peak at 30 degrees above the horizon (see table 3-2).…”

“…The external noise factor fa in equations ( F fao, uniform angular distribution fa = fao dr (00, 00), point source angular distribution for a source at 0= 0 0, 0=0o (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) for a source at 0 = 00, =0…”

“…The input resistance decreases aperiodically to an asymptotic value of 36 ohms as the disk radius increases (see figure 3-7). The input reactance increases aperiodically to an asymptotic value of 22 ohms for a very thin [3][4][5][6][7][8][9][10][11][12][13][14][15][16] monopole element (see figure 3-8). The input reactance is a stronger function of the element radius than the radiation resistance [40].…”