8465

7846

كارشناسي ارشد

مخابرات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1392

نه،67ص.: جدول، نمودار

ص.ع.به فارسي و انگليسي

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ابوالقاسم زيد آبادي نژادي

7/11/92

مهندسي برق و كامپيوتر

ID7846

به فارسي و انگليسي قابل رويت در نسخه ديجيتالي

Large signal Modeling of GaN HEMTs Transistors for Design of Microwave Power Amplifiers Majid Lorestani m lorestani@ec iut ac ir Date of Submission 2013 06 18 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Reza Safian rsafian@cc iut ac irAbstractIn the recent decade because of the larger energy gap and higher thermal conductivitythan GaAs the GaN semiconductor has been reaching attention in high powerapplications Because of these properties GaN has the ability to work in high tempratureand high voltage conditions Besides the above properties the electron saturation velocityin GaN is higher than GaAs that make s this semiconductor proper for high frequencyapplications In High Electron Mobility Transistor HEMT with GaN technology whichthe first kind was made in 1993 the junction of GaN AlGaN which have differentenergy gaps is used The reason to use it is to make free electron layer in the transistorchannel For designing a large signal amplifier using a GaN HEMT transistor we need alarge signal model for the transistor which properly charactrise s it s behavior Despite thenoble properties of the AlGaN GaN HEMTs transistors one of the main problems withthis kind of transistors is the loss of the drain current cause of the impurities in the activearea These impurities can absorb and release a sufficient proportion of electrons to makechange in the voltage current characteristic of transistor Because of the application ofthese transistors in high power the consuming power is high too and this makes the innertemprature of transistor to go high As the the temprature increases the electrons ratedecreases thus the drain current and output power of the transistor decreases In this thesisthe large signal modelling of a GaN HEMT transistor is done by applying tentativemodelling The first step in large signal modelling is small signal modelling Small signalmodel of a transistor can be devided into two parts parasitical and nonparasitical and forthe extraction of nonparasitical elements of the transistor the parasitical elements shouldbe first extracted In this thesis the parasitical elements of transistor are extracted by usingresults of measurments and mathematical relations in low frequency Results ofsimulation show that the used this method in extraction of parasitical elements have

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