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

[02187444]本提案解决了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的设计和实现。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，前者具有微波高效电路的专业知识，后者具有可调谐射频MEMS的专业知识。更具体地说，该项目将侧重于开发用于所有通信硬件发射部分的多频段射频功率放大器。目标是演示使用MEMS开关在毫秒尺度上适应多波段发射机操作（例如，5.7 ghz和24 ghz未授权频段）的调谐阻抗，从而提高总体平均效率和多频段频率覆盖范围。因此，开关模式PAs （E类和F类）将使用多波段MEMS输出电路和可重构MEMS输入电路进行调谐。还将研究使用多波段高效pa的偏置和驱动控制的线性化，主要目标是证明这些放大器对于需要线性的调制方案是有利的。这项工作的结果将对全球商用无线系统从2G过渡到更高标准产生直接影响，在更高标准中，射频前端必须在各种调制方案下支持多频段操作。它还可能导致革命性的小型化负载-拉力系统，取代目前笨重且非常昂贵的负载-拉力系统。提出的解决方案符合下一代通信系统的低功耗、小尺寸、低重量和低成本要求。拟议的努力为期三年，期间将完成下列工作：利用MEMS设计和演示一个多波段阻抗调谐器设计和演示一个多波段高效功率放大器，使用开关模式拓扑（如E类或F类），在两个输出和输入匹配电路之间进行简单的切换，使用动态驱动和偏置控制研究多波段高效饱和PAs的线性化放大器和调谐器的集成，晶体管与调谐器的集成，用于小型化MEMS负载拉将辅以教育活动，将研究成果纳入两所大学的课程和其他有关的外联努力。GIT和CU将为pi提供每学期访问合作者的旅费，并为本科生和研究生提供研讨会。pi计划提出REU项目，以及UROP、SMART和SIRFs（由各自大学资助的本科生研究和少数民族项目），以便理工学院的本科生在夏季在科罗拉多大学工作，科罗拉多大学的学生在理工学院工作一个学期，目标是两所大学之间的研究生招生计划。研究人员将遵循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研究结果。

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.