Fourier series analysis of damped broadband monopole antenna

A method for the calculation of the current distribution along the antenna and, thus, the input impedance is the Fourier series approach. This method is well established and was used by Zuhrt (1953), Duncan and Hinchcy (1960) and Wunsch (1988, 1998), however, it implies sonic problems. When the current distribution becomes more complicated, e.g. due to a thin gap at the driving point, the number of coefficients for the series increases. A second problem is the current near the feeding point, which is the point of interest to calculate the input impedance. King (1956) demonstrated that the imaginary part of the current at the feeding point is not calculated correctly by Zuhrt. We demonstrated that by improving the theory of Zuhrt the current distribution near the driving point can be calculated sufficiently exact. The impact of distributed damping is calculated easily because every distribution of the damping can be expressed in a Fourier series.