Application of spline-based expansion and weighting functions for an efficient analysis of thin-wire structures

An analysis of thin-wire antennas and scatterers using quadratic spline-based expansion and weighting functions within the method of moments (MoM) is presented. So-called quadratic B-splines are introduced as a generalisation of the well-known rectangular and triangle expansion functions. The thin-wire version of the electric-field integral equation (EFIE) is solved by the method of moments (MoM) using Galerkin´s method. The described procedure results in a symmetrical structure of the impedance matrix, which allows the application of symmetric solvers with the benefit of a very effective solving procedure. Due to the choice of the expansion and weighting functions the results are very precise for near-fields and points near the structure. It become possible to investigate structures with very small separations between the wires. Numerical examples demonstrate the suitability of the method for the EMC-analysis and show the advantages of a reduced solving time in the analysis of large systems and a lower limit for the shortest separation between two wires