Small-signal, high-frequency theory of field-effect transistors

In this theory a field-effect transistor of planar geometry is considered as an active, distributed, nonuniform transmission line. The wave equation of this line is determined and solved by an approximation method. From this solution the y parameters are determined. By comparing the results for y 11 with van der Ziel's expression for the high-frequency gate noise of field-effect transistors, it is shown that the noise temperature of y 11 is of the order of the device temperature. The conductance part g 11 of y 11 varies as ω2over a wide frequency range. The high-frequency cutoff of the field-effect transistor is determined.