ULTRA-WIDEBAND 170 AND 240 GHZ CW SOURCE SWEEPING SYSTEMS

超宽带 170 和 240 GHZ CW 源扫描系统

• 批准号: 8172102
• 负责人: CURT R DUNNAM
• 金额: $ 0.09万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8172102
• 关键词: Area; Computer Retrieval of Information on Scientific Projects Database; Custom; Development; Diagnostic; Electron Spin Resonance Spectroscopy; Evaluation; Frequencies; Funding; Grant; Institution; Investigation; Measurement; Methods; Output; Performance; Phase; Predisposition; Procedures; Research; Research Personnel; Resources; Services; Source; Staging; System; Techniques; Testing; United States National Institutes of Health; Work; base; design; design and construction; improved; instrumentation; millimeter; operation; programs

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Verification and tuning procedures related to bridge setup for ESR spectroscopy are, in general, greatly facilitated by swept-frequency measurement of transmitted/reflected power. Swept-frequency evaluation methods are especially useful in the millimeter-wave regime, and even more so when quasioptical techniques are employed, mainly due to the numerous interacting adjustments and enhanced quasioptical bridge susceptibility to extra-path reflections. As useful as swept measurement capability is, off-the-shelf test and measurement instrumentation providing phase-locked swept-frequency capability at even the lower millimeter-wave regime (i.e., below 100 GHz) is inordinately expensive and, above that frequency range, appears to be available only on an even more expensive custom-built basis. For this reason, ACERT had not previously invested in millimeter-wave swept-measurement capability for its 170 and 250GHz c.w. spectrometer bridges. Last year, ACERT acquired significantly improved millimeter-wave sources of center frequencies at 170 and 240 GHz for its high-field c.w. quasioptical ESR spectrometers. These units generate approximately 12dB more output power than the previous c.w. sources and provide phase-locked operation over a relatively broad frequency range of fc ¿ 5 GHz. In view of the significantly higher output power available from these sources, an extensive program of bridge and resonator design upgrades was undertaken for optimized bridge operation in inductive-reflection mode. During the course of this development work, it became evident not only that swept-frequency measurement capability would be indispensable, but also, conveniently, that these extended-range c.w. sources might be pressed into service for such incidental use. Our work to date in this area has resulted in an interim 170GHz swept-frequency system which has proven extremely useful in the setup and fine-tuning of the H.F. reflection bridge. We have found that, although the swept output power is not actively leveled, the source multiplier stage bias levels may easily be tuned to provide better than 1.2 dB flatness at fc ¿ 1.0GHz and approximately 3dB over the entire source tracking range from 165 to 175GHz. This performance level is more than sufficient for general bridge and resonator tuning procedures. Given the encouraging results thus far, we plan to continue this project over the coming year with similar investigation of the new 240GHz tracking c.w. source for swept measurements. During the coming year, we plan to continue with the design, construction, installation and programming of a simplified operator interface for switching between normal c.w. operation and the swept-frequency diagnostic modes.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 与ESR光谱的电桥设置相关的验证和调谐程序通常通过透射/反射功率的扫频测量来极大地促进。扫频评估方法是特别有用的毫米波政权，甚至更是如此，当采用准光学技术，主要是由于众多的相互作用的调整和增强的准光学桥敏感度额外的路径反射。与扫频测量能力一样有用的是，现成的测试和测量仪器在甚至较低的毫米波状态（即，低于100 GHz）是非常昂贵的，而高于该频率范围，似乎只能在甚至更昂贵的定制基础上才能获得。出于这个原因，ACERT以前没有投资于其170和250 GHz c.w.的毫米波扫频测量能力。光谱仪电桥 去年，ACERT为其高场连续波获得了中心频率为170和240 GHz的显著改进的毫米波源。准光学ESR光谱仪。这些单元产生的输出功率比以前的c.w.源，并在fc <$5 GHz的相对较宽的频率范围内提供锁相操作。 考虑到这些光源的输出功率显著提高，我们对电桥和谐振器设计进行了广泛的升级，以优化电感反射模式下的电桥工作。在这项开发工作的过程中，很明显，不仅扫频测量能力是必不可少的，而且方便的是，这些扩展范围的连续波测量能力可能会为了这种偶然的用途而将源压入服务。 迄今为止，我们在这一领域的工作已经产生了一个临时的170 GHz扫频系统，该系统已被证明在高频的设置和微调中非常有用。反射桥我们已经发现，尽管扫频输出功率没有主动调平，但是源倍增器级偏置电平可以很容易地被调谐，以在fc <$1.0GHz处提供优于1.2 dB的平坦度，并且在从165到175 GHz的整个源跟踪范围内提供大约3 dB的平坦度。这种性能水平对于一般的电桥和谐振器调谐程序来说是绰绰有余的。鉴于迄今为止令人鼓舞的结果，我们计划在未来一年继续这一项目，对新的240 GHz跟踪c.w.用于扫描测量的源。在未来一年，我们计划继续设计、建造、安装和编程简化的操作界面，以便在正常的c.w.操作和扫频诊断模式。