Abstract
This article presents an efficient implementation of an iterative method that includes fast mode transformations (FMTs). This method has the advantage of simplicity in that it does not involve basis functions and inversion of matrices, as used in other calculation methods. Therefore, it is capable of analyzing larger bodies than other classical techniques. An implementation of the iterative calculation is shown for the extraction of S parameters of unbounded multiport microstrip passive circuits. The good agreement between simulation results and experimental data (Zhu & Wu, 1997) justifies the design procedure and validates the present analysis approach.