Application of Spline-Based Expansion and Weighting Functions for an Efficient Analysis of Thin-Wire Structures with Small Separation between the Wires

An analysis of thin-wire antennas and scatterers using quadratic spline-based expansion and weighting functions is presented. The known spline-expansions are generalised to handle wires with segments of unequal length. The thin-wire version of the electric- field integral equation (EFIE) is solved by the Method of Moments (MoM) using Galerkin’s method. To utilise the advantages of these assumptions for solving critical problems, the solution of the so-called potential integrals must be done very carefully. The described procedure has mainly two features. It yield to very accurate near-field results with the outcome of a shorter lower limit for the smallest distance between two wires and it produces a symmetric impedance matrix, which allows the application of symmetric solvers. Numerical examples demonstrate the suitability of the method for the EMC-analysis.