We present a novel methodology to extract model parameters from measured S-parameter for silicon on-chip spiral inductor. The current approach is based on the analyses of a set of characteristic functions, which exhibit well-defined linear dependence on other functions or variables such as omega(2) in certain frequency range, and the model parameters can be derived from the linear coefficients of the characteristic functions. As demonstrated for a nine-element single-pi equivalent circuit, the extracted parameters can simulate the inductor with a good precision over broad frequency up to 10 GHz. (C) 2004 Elsevier Ltd. All rights reserved.