Feature Selective Validation (FSV) Application to S-Parameter Models Directly

In this paper, datasets using complex numbers are applied to the Feature Selective validation (FSV) algorithm directly making full use of the original algorithm. The Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) in the standard FSV algorithm support complex number by nature although the currently available FSV tools do not support it. The distance in complex number plane is more reasonable to measure the error between two complex numbers than the weighted errors by real and imaginary parts, or magnitude and phase parts, separately. A complete flow chart is designed and implemented to deal with the standard S-parameter data file in Touchstone format. To serve for most Signal Integrity/Power Integrity (SI/PI) design applications, the FSV is applied element by element on the whole S-matrix. The FSV results include Point-by-Point Mean Value Amplitude Difference Measure (ADM), Feature Difference Measure (FDM), Global Difference Measure (GDM), and Grade and Spread can be displayed in 3D Bar format on every element of the whole S-matrix. The Confidence Histograms of each S-Matrix element for ADM, FDM, and GDM can also be displayed. Several practical application examples are displayed including 12-port printed circuit board (PCB) via S-parameter models derived from electromagnetic simulation tool. The application examples show easy usage of the method to compare two Touchstone S-parameter models in practical SI/PI design.