Micromachined Standards for Calibrated Millimeter and Submillimeter-Wave Network Measurements

巴克智能优点：在微波和毫米波系统的开发中发挥关键作用的测试和测量基础设施要么稀缺、昂贵和复杂，要么频谱的大部分太赫兹区域(也称为亚毫米区域，通常被认为是从300 GHz扩展到3 THz的频段)不存在。目前，为太赫兹应用设计的设备和子系统主要依赖于比例模型--在设备或子系统集成到完整的仪器之前，通常不可能完全表征它们的性能。六端口反射仪能够使用相当简单的功率探测器电路来测量精确的散射参数。这种方法的优点是，与更复杂的矢量网络分析仪相比，它更容易扩展到太赫兹频率范围。然而，这项技术需要两步校准技术。第一步是使用滑动终端，它在复数反射系数平面上划出一个圆，这允许将六端口转换为等效的四端口反射计。然后使用网络分析仪校准的标准技术(例如，短路-空载)。不幸的是，在100 GHz以上，这些滑动终端并不是特别健壮，这导致了校准中的重大误差。因此，本项目将专注于校准六端口分析仪的测量标准的模拟和设计。滑动终端可以使用分布在短路或开路传输线上的RF-MEMS变容二极管来电子实现。RF-MEMS可变电容是这种应用的理想之选，因为可以实现恒定的损耗和相移。然而，在亚毫米波频率，RF-MEMS波束内的寄生电容和电感将显著减少可实现的相位变化量。因此，本项目将研究在亚毫米范围内增加RF-MEMS器件可实现的相位变化的新方法。更广泛的影响：这项研究计划将加强和支持弗吉尼亚大学的一些重要研究、教学和推广活动。此外，根据这笔赠款开展的工作将是通过为仪器校准提供可靠和精确的MEMS标准，为亚毫米光谱和仪器建立测量基础设施的重要一步。虽然这项工作的大部分最初影响将被直接依赖毫米波和亚毫米波技术的社区感受到，但这项研究也将使新兴应用受益，如化学和生物制剂传感、大规模雷达距离系统和超宽带通信。这项计划最重要的受益者将是弗吉尼亚大学和其他涉及高频设备、毫米波工程和亚毫米仪器研究的机构的研究生和本科生。此外，我们在弗吉尼亚大学的研究团队与弗吉尼亚二极管公司以及国家射电天文台中央开发实验室有着密切的合作关系，弗吉尼亚二极管公司是一家专注于将太赫兹技术推向市场的小公司。

0501391BarkerIntellectual Merit: The test and measurement infrastructure that has played such a pivotal role in the development of microwave and millimeter-wave systems is either scarce, expensive and complex, or does not exist for much of the terahertz region of the spectrum (also known as the submillimeter region and generally regarded as the frequency band extending from 300 GHz to 3 THz). At present, the devices and subsystems being designed for terahertz applications rely primarily on scaled modeling - full characterization of their performance is generally not possible until the device or subsystem has been integrated into a completed instrument.The six-port reflectometer is capable of measuring accurate scattering parameters using fairly simple power detector circuitry. The advantage of this approach is that it is more easily scaled up into the terahertz frequency range than the more complex vector network analyzers. However this technique requires a two-step calibration technique. The first step involves the use of a sliding termination that traces out a circle in the complex reflection-coefficient plane which allows the sixport to be converted to an equivalent four-port reflectometer. This four-port is then calibrated using the standard techniques for network analyzer calibration (ex. short-open-load). Unfortunately, above 100 GHz these sliding terminations are not particularly robust which leads to significant errors in the calibration. Therefore, this project will focus on the simulation and design of measurement standards for calibrating six-port analyzers.A sliding termination can be implemented electronically using RF-MEMS varactors distributed along a short- or open-circuited transmission line. The RF-MEMS variable capacitance is ideal for this application due to the fairly constant loss versus phase shift that can be achieved. However, at submillimeter-wave frequencies the parasitic capacitance and inductance within the RF-MEMS beam will significantly reduce the amount of phase variation that can be achieved. Therefore, this project will investigate novel methods of increasing the achievable phase variation from RF-MEMS devices in the submillimeter region. Broader Impacts: This research program will enhance and support a number of important research, teaching, and outreach activities at the University of Virginia. In addition, the work to be carried out under this grant will be an important step in building a measurement infrastructure for the submillimeter spectrum and instrumentation by providing reliable and precise MEMS standards for instrument calibration. Although most of the initial impact of this work will be felt by the communities that rely directly on millimeter and submillimeter-wave technology this research will also benefit emerging applications such as chemical and biological agent sensing, scaled radar-range systems, and ultra wideband communications.The most important beneficiaries of this program will be the graduate and undergraduate students at the University of Virginia and other institutions involved in high-frequency devices, millimeter-wave engineering, and submillimeter instrumentation research. In addition, our research team at the University of Virginia has close collaborative ties with Virginia Diodes, Inc., a small company focused on bringing terahertz technology to market, as well as the National Radio Astronomy Observatory's Central Development Laboratory.