RF Power Amplifier Spectral Regrowth -Causes and Cures

9900085 jemison本提案描述了对射频（RF）功率放大器频谱再生的基本机制的系统调查，这是无线通信行业的一个关键问题。这些机制包括瞬态（即记忆）效应，由于固有晶体管器件结构，输入/输出匹配和偏置网络阻抗导致的捕获和相位畸变。以前报道的这方面的工作是不完整的、碎片化的和矛盾的。该研究分为几个容易识别的任务：任务一详细建模和分析ofet相位失真；任务二研究瞬态记忆效应对频谱再生的影响；任务三宽带行为信号建模开发；任务一旨在确定FET相位失真的原因，这一问题仍然存在激烈的争论。任务II是我们全部工作的主要部分，它将利用Lehigh大学的Leoni等人最近的工作，该工作解决了脉冲调制激励下GaAs FET功率放大器中的瞬态效应[1]。这项工作将首次扩展到包括瞬态对复杂信号（如码分多址（CDMA））输出频谱的影响。与输入/输出匹配和偏置电路阻抗相关的频谱再生效应（迄今尚未系统研究）也将进行研究。任务H的目标是对瞬变对光谱再生产生的影响有一个基本的了解，并开发设计技术来减轻这些影响。任务IH利用了拉斐特学院最近的行为建模工作。这项任务的目标是开发一种可以应用于新波形（如宽带CDMA）的行为模型。从这些研究中获得的知识将应用于开发更好的大信号晶体管模型和行为电路模型，这些模型可以处理复杂的数字调制信号，如CDMA。这些模型将通过使用我们的工业合作伙伴Anadigics， Inc.提供的设备进行新颖和广泛的测量来验证，Anadigics, Inc.是无线通信行业射频功率放大器的全球领先供应商。这项工作的结果将导致改进射频功率放大器的建模和设计程序的发展，用于数字通信应用

9900085JemisonThis proposal describes a systematic investigation into the fundamental mechanisms that contribute to radio frequency (RF) power-amplifier spectral regrowth, a critical issue for the wireless communications industry. These mechanisms include transient (i.e. memory) effects associated with trapping and phase-distortion due to the intrinsic transistor device structure, input/output match, and bias network impedances. Previously reported work in this area is incomplete, fragmented, and contradictory. The proposed research is divided into several easily identifiable tasks: Task I Detailed modeling and analysis ofFET phase distortion Task II Investigation into transient memory effects on spectral regrowth Task III Wide-band behavioral signal modeling developmentTask I is intended to determine the cause of phase distortion in the FET, an issue that is still hotly debated. Task II, which comprises the majority of our total effort, will leverage the recent work of Leoni, et. al. at Lehigh University which addressed transient effects in a GaAs FET power-amplifier under pulse modulation excitation[I]. This work will be extended to include, for the first time, the effects of transients on the output spectrum of a complex signal such as Code Division Multiple Access (CDMA). Spectral regrowth effects associated with input/output match and bias circuit impedance )which have not been systematically studied to date) will also be investigated. The goals of Task H are to develop a fundamental understanding of the effects of transients on spectral regrowth generation and to develop design techniques to mitigate these effects. Task IH leverages recent behavioral modeling work at Lafayette College [2]. The goal of this task is to develop a behavioral model that can be applied to new waveforms such as wide-band CDMA.The knowledge gained from these investigations will be applied to develop better large-signal transistor models and behavioral circuit models that can handle complex digitally modulated signals such as CDMA. These models will be validated by novel and extensive measurements using devices provided by our industrial partner, Anadigics, Inc., a leading worldwide supplier of RF power-amplifiers for the wireless communications industry. The results of this work will lead to the development of improved RF power-amplifier modeling and design procedures for digital communication applications.***