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 2^nd 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.