Efficient Calculation of Input Impedance of Dipole Antennas

An efficient method for the calculation of input impedance of dipole antennas is proposed. The equivalent magnetic current frill is used to model the coax aperture. The characteristics of the feed model by the equivalent magnetic current frill are researched and a simple method for calculation the near and far zone fields from an annular ring of circumferentially directed magnetic current which may be used to represent coaxial apertures is presented. Based on this, the EFIE for arbitrarily shaped thin wires (ATW) is adopted to model the variation of the current, and the moment of method is used to calculate the input impedance of dipole antennas with using triangle basis and testing functions. The numerical results are presented to validate the method.