The circumferential variation of the axial component of current in closely spaced thin-wire antennas

Closely spaced thin-wire antennas are analyzed by the moment method using the piecewise-sinusoidal function to describe the current variation along the length of the wire and a Fourier series for the circumferential variation. Data are presented for the circumferential variation of the surface current density of parallel dipoles obtained by the "thin-wire" theory, wire-grid model, and the present formulation. It is found that there is substantial circumferential variation, even for dioples spaced more than several wire diameters.