Method for measuring impedance of monopole antennas in the range 10-100 MHz

A method is proposed for measuring impedances of monopole antennas and for checking the accuracy of the antenna design which does not require a large ground plane. Instead, it is proposed that the impedance measurements be performed for the antenna above a system of radial wires of relatively small length (of the order of one quarter wavelength or shorter at the lowest frequency of interest). These wires are mounted at a certain height above ground, in order to avoid the influence of the ground. However, the measured impedance thus obtained should not be compared with the theoretical impedance of the monopole antenna above infinite ground plane. It must be compared with the impedance computed for the same model, i.e. for the monopole antenna above the described system of radial wires. Thus, the proposed method enables a check to be made not only of the impedance of a particular antenna, but also of the complete design procedure, using a very simple and cheap impedance-measuring site.