Macro Basis Functions for Efficient Analysis of Thick Wires in the MoM

This article presents a macro basis function (MBF) formulation for efficient method of moments (MoM) modelling of conducting wires with appreciable thickness. General surface formulations are prohibitively inefficient for electrically thin wires, while the typical exact-kernel, rooftop-basis, thin-wire MoM becomes wholly inaccurate for electrically thick cylinders. The MBF formulation bridges the gap between thin-wire MoM, and general conducting surface MoM formulations, by introducing circumferential variations and components beyond the standard rooftop basis functions. The MBFs are constructed upon a full-order, divergence-conforming, triangle element MoM discretization. Comprehensive junction and end-cap treatment, and tapered wire support, are natural features of the formulation. As with thin-wire MoM, degrees of freedom (DoFs) are purely proportional to the electrical length of the wire. Results demonstrate that the intermediate range of "thick wires" is analyzed with practically the same accuracy as general surface MoM, with significantly reduced DoFs.