Accurate Time - Domain Modeling of Multi-Finger pHEMT layout Structure based on Transmission line Theory

In this paper, a fully distributed modeling of double gate InGaAs pHEMT as a 5-line active coupled transmission line is described. In order to apply the transmission line theory, a proper equivalent lumped circuit model is allocated for the differential length of the double gate quintuple line transistor and the active multi-conductor transmission line equations are obtained. The passive element values are extracted through numerical analysis and conversion of the single gate active small signal model to the double gate one is performed by an introduced scaling method. These equations are solved by the finite difference time domain technique. The simulation results are compared with the results of conventional slice modeling which are in agreement at low frequencies but show differences, at high frequencies.