On the suppression of asymmetric artifacts arising in an implementation of the thin-wire method of moments

The original version of the thin-wire frequency-domain moment-method program developed by J.H. Richmond (1974) has been modified to suppress the computation of nonphysical asymmetric fields. Richmond's implementation uses piecewise sinusoidal expansion and testing functions, along with filamentary current approximations. The modified version, termed the bridge-current version, is described. The original program and the modified version are compared with each other and with simplified theory, where applicable, on the following symmetrical structures: a rectangular wire loop, a two-wire transmission line, and a log-periodic dipole antenna. The bridge-current version is shown to eliminate the computation of nonphysical asymmetric fields, to be essentially invariant with respect to variations in segmentation for the above-mentioned structures, and to produce results that compare well with simplified theories where applicable. It is noted that the bridge-current version is particularly advantageous for structures that include close-spaced parallel wires connected by short wire segments.< >