مرکز منطقه ای اطلاع رساني علوم و فناوري - An experimental investigation on the behavior of the dipole antenna near the interface between the conducting medium and free space

Abstract :

An experimental study was made of the driving-point admittance and the relative amplitude and phase distributions of the current for a dipole antenna near and parallel to the interface between the conducting medium and free space. (The antenna was always located in the conducting medium, unless otherwise specified.) The depth $d$ of the antenna from the interface was varied from $d/\\lambda =4.4$ to 0. The loss tangent $\\sigma /\\omega \\epsilon_{r}\\epsilon_{0}$ of the conducting medium was varied from 0.036 to 8.8, a range which includes a variety of media such as poor insulators, the ionosphere, plasmas, dry earth, wet earth, lake water, and sea water. The antenna height $\\beta h$ in radians was varied from $\\beta h=0.1$ through $2\\pi$ . Comparisons were made, wherever possible, between the characteristics of the dipole antenna in the half space and in a space completely filled with the dissipative medium. The driving-point admittances in the limiting case $d\\rightarrow \\infty$ are in good agreement with the available theories by King and Harrison [1], and Wu [2], which have already been verified experimentally by Iizuka and King [3]. Since all measured results are given in terms of dimensionless parameters such as $\\beta h,d/\\lambda _{u},\\sigma /\\omega \\epsilon_{r}\\epsilon_{0}$ , and $1/\\sqrt {\\epsilon_{r}}$ , they may be applied to any combination of conductivity, frequency, dielectric constant, and distance of the antenna from the interface [4].