Abstract: A new modified single-π equivalent circuit model for on-chip spiral inductors is presented.It shows a good fitting result between the simulated data of this model and the EM simulated data in HFSS over a wide frequency range.The proposed model takes full account of the substrate coupling effect,the skin and proximity effects at high frequencies,component parameter values of the circuit are analytically extracted based on Y-parameters using the method of quasi-linear functions and the two-port network analysis derived from EM simulation without any optimization.As applied to the symmetric single-π equivalent circuit,it can simulate the frequency variation characteristics of different parameters for on-chip spiral inductors with a high precision from 0 to 20GHz,and verify the accuracy of the equivalent circuit model.