Small signal properties of field effect devices

The small signal properties of field effect devices are treated analytically. The analysis is based upon an active, distributed transmission line analogy to the conductive channel of field effect devices. Within the limitations of the gradual channel approximation, a general analysis is presented which is applicable to both junction and MOS field effect devices. Equivalent circuits are obtained which describe field effect device characteristics in the region below saturation as well as in the current saturation region. Effects of parasitic elements on the terminal y parameters in practical devices are considered. Specific device models are considered for junction devices and MOS devices and the more important equivalent circuit parameters are evaluated in terms of the dc terminal voltages.