| Mobile communications drive a multitude of advancements in RF and microwave semiconductor devices and circuit technologies.While these advancements have en-abled the mobile communication revolution,they also provide circuit and system de-signers with many different options and approaches for product realisation.The days when designers simply optimised a Gallium Nitride integrated circuit to achieve sat-urated output power and higher efficiency are long gone.Today circuit and systems engineers have to know more about the whole process of product development.De-vice physics,modelling,characterisation,circuit design,architecture and application,signal modulation formats,measurements,and industry standards are all required to successfully design modern receiving and transmitting components.The cost balance,performance,and cycle time as well as simultaneously meeting challenging product specifications must be taken into account in many engineering and design decisions.Specific examples would be selecting an optimum semiconductor technology,device characterisation and modelling,circuit architecture,linearization strategy,and overall system-level considerations.The importance of microwave transistor modelling comes from the fact that transistors are the critical components in high-frequency circuits,which are the core of modern wireless communication systems such as mobile devices etc.We are currently witnessing a proliferation of wireless communication applications and continuous progress in transistor technologies that make high-frequency transistor modelling a hot topic.Moreover,wide-bandgap semiconductors like GaN HEMTs are excellent for circuits,design,and production.Like high linearity and highly efficient power amplifiers,AlGaN/GaN HEMTs are promising wide-bandgap devices as they combine the material properties of GaN with the operating principle of HEMTs.This dissertation provides an enhanced Angelov large-signal model by incorporat-ing the trapping effect that was later added to the library of CAD tools for more robust designing of circuits.Secondly,the modified large-signal model was verified by design-ing a power amplifier in the CAD tool.Thirdly,the large-signal model of BP RTD diode was also transformed to tangent hyperbolic from exponential to 2D materials RTD.The first part of this dissertation covers the Angelov extraction method for a large-signal model.The sequence of extracting the parameters for the GaN HEMT transistor is described,and at the end the transistor model is implemented in the CAD library to design high-power amplifiers.The first part also describes a de-embedding technique for small and large-signal analysis.The second part of this dissertation focuses on a new method of an Angelov model,used to extract the DC part of the large-signal model for the GaN HEMT transistor with trapping and self-heating effects.The Angelov model lacks the trapping effect.This enhanced Angelov model exhibits good accuracy and stable behaviour as compared with the current models available on the market such as the EEHEMT,Stratz and An-gelov.The results were compared with the enhanced Angelov method which extract self-heating effects and dispersion phenomena only,but lacks trapping effects.Finally,the Angelov drain current equation is modified with trapping impact,giving the new concept of the large-signal model with trapping effects.In the third part,the Doherty power amplifier design is carried out by using new and old Angelov model to achieve high PAE,high linearity power,and gain for a 5G application.And clearly show the improvement of new model in applicationIn the fourth part,the modelling of black phosphorus BP is prepared to extend our modeling strategy methodology established by transformation from an exponential to a better tangent hyperbolic function which better represents 2D materials.In conclusion,an enhanced Angelov GaN HEMT large-signal model with trap-ping effects was developed and used to design a power amplifier for future wireless 5G communication. |
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