Extraction of causal RLGC models from measurements for signal link path analysis

A method for developing a causal RLGC model from S-parameter measurements is proposed for single-ended transmission lines with the assumption of 2nd order Debye representation for the substrate dielectric medium. Genetic algorithm, an optimization method, is used to find the causal model parameters and the substrate dielectric properties. The measured S-parameter of a stripline with TRL calibration de-embedded is studied based on the proposed method. Good S-parameter agreement among the measurement, the causal RLGC circuit modeling, and the full-wave simulation has been achieved. The time-domain RLGC circuit simulation for pulse propagation along the stripline demonstrates that the developed model is causal. The comparison of eye-diagrams generated from S-parameters between the modeling, including RLGC circuit and full-wave, and the measurement is shown as well.