【作者】 支传德；

【导师】 杨华中；

【作者基本信息】 清华大学 ， 电子科学与技术， 2006， 博士

【摘要】 射频功率放大器是现代无线通信、雷达、电子对抗等系统收发前端的关键组件之一,它的稳定工作是系统正常运行的必要条件,它的线性度直接影响非恒定包络调制系统的性能,所以射频功率放大器的线性化和稳定性始终是射频电子学研究的热点和难点。本论文研究了用于无线通信的射频功率放大器的线性化和稳定性,完成了以下工作:1)包络消除与恢复技术能同时提高射频功率放大器的效率和线性度,本文提出了一种新的分析其交调失真的方法,建立了交调失真随包络通道带宽和包络相位延时差变化的通用简化模型,该简化模型克服了Raab模型只能处理零延时差和无穷包络通道带宽这两个特例的局限性;采用本文模型得出的交调失真等高线图还可以帮助设计者快速准确地选择电路参数。2)针对包络消除与恢复结构的特点,提出了一种全新的在基带进行自适应调整延时的线性化方法,这种方法适用于宽带功率放大器的线性化,对于信号带宽为11MHz的IEEE 802.11b宽带无线通信系统,根据这种线性化方法设计的射频功率放大器,能有效达到系统谱罩要求。通过对环路模型的分析,可以得到延时补偿值与包络信号带宽、包络通道带宽等之间的关系。3)基于深亚微米CMOS工艺,运用系统辨识的方法分析了射频功率放大器在大信号模式下的稳定性问题,运用反馈网络,消除了射频功率放大器的的不稳定极点,进而消除了可能出现的分谐波振荡。4)使用0.18μm的CMOS工艺,分别设计了带稳定电路和不带稳定电路的功率放大器,根据测试结果,分析了深亚微米工艺下电路参数变化对整个功率放大器稳定性特别是对潜在的分谐波振荡的影响。更多还原

【Abstract】 The radio-frequency (RF) power amplifier (PA) is one of the key components of transceiver front-ends for modern wireless communication systems, RADAR, and electronic countermeasure. Its stability is necessary for system working and its linearity directly affects the performance of non-constant envelope modulation system. Thus the linearization and stabilization of RF PAs are always the hotspot and difficulty of RF electronic research. The linearity and stability of RF PAs for wireless communication are analyzed in this dissertation. The principal contributions of this dissertation include:The envelope elimination and restoration (EER) technique has been widely applied to improve the efficiency and the linearity of RF PAs simultaneously. A new method is proposed to analyze the intermodulation distortion (IMD) of RF PAs with EER. A general simplified model for IMD is founded which varies with the bandwidth of envelope path and the differential delay between envelope and phase signals, and overcomes the limitation of Raab’s model which can only solve such two specific instances as zero differential delay and infinite bandwidth of envelope path. A contour map derived from the general model in this dissertation is helpful for the designers to choose circuit parameters quickly and accurately.A novel adaptive delay-control method, implemented in the baseband, is presented to improve the linearity of RF PAs with EER. This method can be applied to the linearization of wideband PAs and makes the RF PAs easy to meet the spectral mask specification of IEEE 802.11b wireless communication systems with 11MHz-bandwith effectively. The relationship between the compensated delay and the bandwidth of envelope signal and envelope path comes out by the analysis for loop model. Based on deep sub-micron CMOS technology, the stability of PA operated beyond large signal is analyzed by system identification method. The sub-harmonic oscillation is eliminated by feedback network which removes the unstable poles of PA.The PAs are fabricated with and without stabilization circuit respectively. Based on the test results, this dissertation analyzes the effects on stability due to circuit parameter fluctuation, especially on potential sub-harmonic oscillation of PAs in deep sub-micron technology.更多还原