Research method of the field transistors high frequency parameters using network analyzer

The necessity of using a vector network analyzer (VNA) for RF/MW device characterization is shown. Field transistor equivalent circuit has been analyzed for dynamic parameters research. Authors have got analytical expressions and provided method for high-frequency field transistors parameters determination based on s-parameters measurements using a VNA. The recommendations for test transistors' optimal parameters are presented. The device under test in this paper is GaAs HEMT double gate transistor with w=150 um. The research of transistors parameters was done in operating point: Vds=1.4 V, Vgs=-0.6 V. This paper contains method for HEMT transistor capacitance (Cin, Cgd, Cgs) determination using time-domain reflectometry (TDR). Authors have got theoretical and experimental values for fMAX that show good coincidence.