An Improved Transistor Modeling Methodology Exploiting the Quasi-Static Approximation

Anwar Jarndal,Giovanni Crupi,Antonio Raffo,Giorgio Vannini,Valeria Vadala

doi:10.1109/jeds.2021.3067103

Abstract

In this paper, a new modeling technique is proposed for extracting small-signal lumped-element equivalent-circuit models for microwave transistors. The proposed procedure is based on using an optimization approach that is improved by targeting a quasi-static behavior as additional objective function rather than only minimizing the error between the simulated and measured scattering parameters. The validity of the developed modeling methodology is successfully demonstrated by considering a 0.25x1000 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> gallium nitride (GaN) high-electron-mobility transistor (HEMT) as a case study.

Highlights

The small-signal lumped-element equivalent-circuit modeling of microwave transistors has been much debated and is still being debated [1]–[8], since this area of research is of great interest and very challenging
The global optimization techniques are based on the multiple-point initialization instead of the single starting point used in the local methods
The critical problem of the model parameter reliability is successfully addressed by developing a new approach based on targeting quasi-static behavior as an additional objective function. This is because the NQS effects can be disregarded at relatively low frequencies, since they represent the inertia of the intrinsic transistor in responding to rapid voltage changes and they become more evident with increasing frequency

Summary

INTRODUCTION

The small-signal lumped-element equivalent-circuit modeling of microwave transistors has been much debated and is still being debated [1]–[8], since this area of research is of great interest and very challenging. The global optimization techniques are based on the multiple-point initialization instead of the single starting point used in the local methods These points are randomly generated to cover the whole search space and to avoid the initial guess dependency. The critical problem of the model parameter reliability is successfully addressed by developing a new approach based on targeting quasi-static behavior as an additional objective function. This is because the NQS effects can be disregarded at relatively low frequencies, since they represent the inertia of the intrinsic transistor in responding to rapid voltage changes and they become more evident with increasing frequency.

DEVICE UNDER TEST AND CHARACTERIZATION

CONCLUSION