Input impedance of thin dipoles by moment method

The input impedance of half-wave dipoles with decreasing diameters has been calculated using the moment method of analysis with a stepped approximation of the current distribution. It is shown that the solution becomes increasingly inaccurate when the wire radius decreases and only a few segments for the antenna are used, and that it also diverges from the accurate answer when the length/diameter ratio of each segment is such that the axial-line-current and charge approximations become insufficient.