Nonlinear Modeling Research And Power Amplifier Design Of GaN HEMT Power Devices

In recent years,with the rapid development of science and technology,people have put forward higher and higher requirements for the performance of transistors in high temperature,high power,radiation resistance and high frequency.The GaN HEMT as the third generation semiconductor material device,due to its superior performance in high frequency,high temperature,high power,etc.,it gradually became the current research hotspot.However,although GaN HEMT devices have gradually become the mainstream in the industry,in the design software of power amplifier circuits,there is no more accurate GaN HEMT device model for simulation,so the research on the GaN HEMT device model becomes More and more urgent.In this paper,the nonlinear equivalent circuit model of GaN HEMT devices is studied.By analyzing the nonlinear components in the GaN HEMT large-signal equivalent circuit,the GaN HEMT nonlinear component model is divided into a nonlinear I-V model and a nonlinear C-V model.Two parts are studied and discussed.In this thesis,the internal structure and working principle of GaN HEMT devices are discussed in detail,and the nonlinear equivalent circuit model of GaN HEMT devices is studied accordingly.Several common nonlinear models are briefly introduced.Among them,in the comparative analysis of various nonlinear models of GaN HEMT devices,the Angelov nonlinear I-V model was chosen to study the nonlinear DC model,and the Curtice nonlinear C-V model was selected to study the nonlinear capacitance model.In the course of research,we found that the Angelov model chosen in this thesis can describe the DC characteristic of the device well in the nonlinear I-V characteristics,but it cannot achieve high accuracy.After detailed analysis and discussion of the structure and working principle of GaN HEMT devices,combined with other data analysis,this paper determined that the main reason affecting the accuracy of nonlinear models is the self-heating effect of the device.After the reasons that affect the accuracy of the nonlinear model of GaN HEMT devices are attributed to the self-heating effect of the device,this thesis attempts to add a temperature correction factor to the equation of the Angelov nonlinear I-V model to improve the effect due to the device self-heating effect.In the improved formula of the nonlinear C-V model,reference is also made to the influence of the device self-heating effect.After the empirical formula of the nonlinear C-V model is improved,the original fitting effect map and the improved fitting effect map are compared and the improvement is obtained.The high precision of the nonlinear model results in the improvement of the accuracy of the nonlinear C-V model.Finally,after a brief introduction to the basic theory of power amplifier,this thesis uses CREE's GaN-based high electron mobility transistor CGH40010 F to design and debug a center frequency of 5.8GHz.The single-tube output power reaches 5W.About 60% of power amplifiers are achieved.