Comparison Study of Preconditioned Basis Functions in Spectral Domain Analysis of Microstrip

A comparison is presented between two sets of entire domain basis functions with edge singularity for the conventional case of the microstrip transmission line in spectral domain. In order to avoid unphysical solution, spurious roots elimination is introduced. It is shown that a significant difference of convergence properties and relative accuracy for different parameters of structures with both sets of basis functions. It also implies the paper is valuable on the choice of basis functions for best performance.