Radiation efficiency and input impedance of monopole elements with radialwire ground planes in proximity to earth
Abstract
Results for input impedance are reported with attention given to results for the radiation efficiency of a thin quarterwave monopole element with a radialwire ground plane at a small distance above flat earth. Numerical data are appropriated from a methodofmoments optimization of radialwire ground planes for wire element near earth. Radial efficiency and input impedance are calculated as functions of the number and length of the radial wires. Radiation efficiency is found to increase monotonically with increased numbers of radial wires and increased length of monopole element. As the groundscreen density approaches infinity, the input resistance and input reactance asymptotically approach the values of the disk ground plane. Attention is given to the resonances that appear in input impedance and radiation efficiency for low numbers of radial wires, and the effect is attributed primarily to the fact that the currents on the wires are not closely coupled.
 Publication:

Electronics Letters
 Pub Date:
 July 1992
 DOI:
 10.1049/el:19920984
 Bibcode:
 1992ElL....28.1550W
 Keywords:

 Antenna Radiation Patterns;
 Electrical Impedance;
 Ground Effect (Communications);
 Method Of Moments;
 Monopole Antennas;
 Far Fields;
 Perturbation Theory;
 Communications and Radar