A Three-Conductor Transmission Line Model for MOS Transistors

An accurate high frequency small signal model for MOS transistors is presented. In the proposed model, by considering the layout of the MOS transistor, it is considered as a three-conductor transmission line. Then, a set of current-voltage equations are derived for the structure using the transmission line theory. These coupled equations are solved by the Finite-Difference Time-Domain (FDTD) technique in a marching-in-time process. To verify the model, the scattering parameters of a 0.13 m transistor are extracted from the time domain results over the 1–100 GHz frequency band and compared with the results obtained from the available models and commercial simulator. The suggested model can be useful in design of various types of high frequency integrated circuits.