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-parameters by poles and zeros. The results from our proposed method agreed well with experimental data from GaAs FETs and Si MOSFETs. The concept of source-series feedback was employed to analyze a transistor circuit set up for the measurement of the S-parameters. Our method can describe the frequency responses of all transistor S-parameters very easily and the calculated S-parameters are scalable with device sizes. It was also found that the long-puzzled kink phenomenon of S/sub 22/ observed in a Smith chart can be explained by the poles and zeros of S/sub 22/.