Impedance Calculations for Wire Antenna Modelling with Macro Basis Functions

This paper concerns the accurate calculation of wire port impedance using the method of moments (MoM) together with a macro basis function (MBF) discretisation scheme tailored to wire current modelling. The MBFs incorporate circumferential current components and variations, aiming to achieve accuracy comparable to that of general surface MoM modelling while requiring fewer degrees of freedom. The excitation is modelled using a magnetic frill source, consistent with the MBF frame-work. Results for a monopole and helical antenna show that the frill functions well together with the MBFs and that it yields more stable impedance calculations than the widely-used delta-gap source.