Collaborative Research: MEMS Tuners for Multiband High-Efficiency Wireless Transmitter Front Ends

本提案针对需要在多个频段运行的下一代通信系统的自适应射频前端进行设计和实现。自适应射频前端将由科罗拉多大学博尔德分校(CU)和佐治亚理工学院(GIT)合作开发，前者拥有微波高效率电路的专业知识，后者拥有可调谐射频MEMS的专业知识。更具体地说，该项目将专注于开发用于所有通信硬件的发射机部分的多频段射频功率放大器。其目标是演示使用用于多频段发射机操作的MEMS开关(例如，5.7 GHz和24-GHz非许可频段)在毫秒尺度上自适应调谐阻抗，从而产生更大的总体平均效率和多频段频率覆盖。为此，开关模式功率放大器(E类和F类)将使用多频段MEMS输出电路和可重新配置的MEMS输入电路进行调谐。还将研究多频段高效功率放大器的偏置线性化和驱动控制，主要目的是证明这些放大器对于需要线性的调制方案是有利的。这项工作的结果将直接影响全球商业无线系统从2G向更高标准的转变，其中射频前端必须支持在各种调制方案下的多频段操作。它还可能导致革命性的小型化负载拉动系统，取代目前可用的笨重和非常昂贵的负载拉动系统。所提出的解决方案符合低功耗、小尺寸、O使用MEMS设计和演示多频段阻抗调谐器使用开关模式拓扑结构(如E类或F类)设计和演示多频段高效功率放大器，只需在两个输出和输入匹配电路之间进行简单切换研究采用动态驱动和偏置控制的多频段高效饱和功率放大器的线性化研究放大器和调谐器的集成用于小型化MEMS负载脉冲的晶体管和调谐器的集成将由整合研究的教育活动来补充将调查结果纳入两所大学的课程和其他相关的外联工作。GIT和CU将为PI提供访问合作者的旅费，并在每学期为本科生和研究生举办研讨会。除了UROP、SMART和SIRF(由我们各自的大学资助的本科生研究和少数族裔项目)外，PIS计划提出REU项目，以便GIT本科生夏季在CU工作，而CU学生在GIT工作一个学期，目标是两所大学之间的研究生招生计划。调查人员将遵循NSF的报告要求，并将在同行评议的期刊和会议上公布他们的结果。

0218744PopovicThis proposal addresses design and implementation of adaptive RF front ends for the next generation communication systems that will require operation at several frequency bands. The adaptive RF front ends will be developed by a collaboration between the University of Colorado at Boulder (CU) with expertise in microwave high efficiency circuits, and the Georgia Institute of Technology (GIT) with expertise in tunable RF MEMS.More specifically, this project will focus on the development of a multi-band RF power amplifier used in the transmitter sections of all communication hardware. The goal is to demonstrate adaptation of tuning impedances on the millisecond scale using MEMS switches for multiband transmitter operation (e.g., the 5.7 and 24-GHz unlicensed bands), resulting in a larger overall average efficiency and multi-band frequency coverage. For this reason, switched-mode PAs (classes E and F) will be tuned with a multi-band MEMS output circuit and a reconfigurable MEMS input circuit. Linearization using bias and drive control of multi-band high efficiency PAs will also be studied, with the main goal of proving that these amplifiers are advantageous for modulation schemes that require linearity. Results of this work will have direct impact on worldwide commercial wireless systems moving from 2G to higher standards in which RF front-ends must support multi-band operation under various modulation schemes. It could also potentially lead to revolutionary miniaturized load-pull systems that replace the bulky and very expensive load-pull systems currently available. The proposed solution adheres with the low-power, small-size, low weight and low-cost requirements of next generation communication systems.The proposed effort covers a period of three years during which the following will be accomplished: oDesign and demonstration of a multi-band impedance tuner using MEMSoDesign and demonstration of a multi-band high-efficiency power amplifier using switched-mode topologies (such as classes E or F) with a simple switch between two output and input matching circuitsoStudy of linearization of multiband high efficiency saturated PAs using dynamic drive and bias controloIntegration of the amplifier and tuneroIntegration of transistor with tuners for miniaturized MEMS load-pullThe proposed research will be complemented by educational activities that will integrate the research findings into the curriculum of both universities and other related outreach efforts. GIT and CU will provide travel funds for the PIs to visit the collaborator and give seminars to undergraduate and graduate students each semester. The PIs plan to propose REU projects, in addition to UROP, SMART and SIRFs (undergraduate research and minority programs funded by our respective universities), so that GIT undergraduates work at CU in the summer, while CU students work at GIT for a semester, with the goal of a graduate student recruitment program between the two universities. The investigators will follow NSF's reporting requirements and will also publicize their results in peer reviewed journals and conferences.