A novel interpretation of transistor S-parameters by poles and zeros for RF IC circuit design

In this paper, we have developed an interpretation of transistor S-paramete rs by poles and zeros. The results from our proposed method agreed well wit h experimental data from GaAs FETs and Si MOSFET's. The concept of source-s eries feedback was employed to analyze a transistor circuit set up for the measurement of the S-parameters. Our method can describe the frequency resp onses of all transistor S-parameters very easily and the calculated S-param eters are scalable with device sizes. It was also found that the long-puzzl ed kink phenomenon of S-22 observed in a Smith chart can be explained by th e poles and zeros of S-22.