Power Transistor Modeling And RF/Microwave Power Amplifier Design

During recent decades,the performance of the wireless communication system has now become a key issue due to the scarce wireless spectrum resource and the demand for the green communication.As an important component in the wireless communication system,the radio frequency and microwave power amplifier(RF/MW PA)determines the linearity,the efficiency and the bandwidth etc of the system.To achieve a superior performance of the RF/MW PA,three essential elements are necessary: the accurate models for power transistors,the advanced design method and the rich experience in circuit designs.However,there are many problems in the power transistor modeling and the design method of the PA until now.To solve some of these problems,this dissertation presents the research of the neuro-space mapping method of the HBT transistor modeling,and investigates several important design issues of RF/MW PAs for some wireless communication systems.The main contributions of this dissertation are as follows.1.To improve the accuracy of the Agilent HBT model operated in deep-saturation region affected by the distributed effects of large power devices,a large-signal neuro-space mapping model is proposed for HBT,and it has been successfully verified using the symbolically defined devices in ADS software.The simulated results indicate that this proposed model achieves 1.26-fold and 3.15-fold improvements compared with the Agilent HBT model in the non-saturation region and deep-saturation region,respectively.This research provides the experience and the guidance for the improvement of the HBT model using the neuro-space mapping method.2.To solve the large-chip-size problem of the VHF/ UHF ultra-broadband CMOS PA,a three-stage ultra-broadband CMOS PA is proposed to remedy the defects of the existing design methods.This PA achieves a frequency range of 0.1?1.2 GHz and a small chip area of 0.41 mm~2,with a good combination of the power gain,the efficiency and the return loss.To the best of the author's knowledge,this PA achieves the highest Fo M1(Power×Gain×Return Loss×Fractional Bandwidth /Size). The measured results indicate that this integrated PA can fully meet the design requirements of the broadband RF front-end chip applied in the industry network.3.To overcome the bottleneck of the ultra-broadband CMOS PA design in software defined radio(SDR)system,the transistors-stacking technology is successfully implemented in a VHF to C band CMOS PA for the first time.To remedy the defect of the existing method,a corrected equation to analyze the source input impedance of the stacked-FETs is proposed for this CMOS PA.This PA archieves a output power larger than 0.2 W and a 1 d B bandwidth of 0.1?6 GHz with a small chip area of 0.64 mm~2.To the best of the author's knowledge,this PA achieves the highest Fo M2(Power×Upper Limitting Frequency/(Size×Lower Limitting Frequency)).The measured results indicate that this integrated PA can meet the design requirements of the broadband RF front-end chip applied in the SDR system.