Integrating High Frequency Whispering-Gallery-Mode Phononic Cavities with Efficient Electrically-Small Antennas: Pushing the Limits of Wireless Passive Micro-Sensing

该项目旨在探索并将新颖的微型谐振器设计与极小的天线相结合，构建一个不需要电源的无线传感平台，并利用经济规模以极低的价格提供卓越的性能。该平台一旦实现，将通过提供远程和非侵入式患者生命体征测量的灵活性，对医疗传感范式产生重大影响。尽管过去几十年来微电子领域取得了巨大的技术进步，但医疗行业使用的传感设备的规模与微型传感器领域的最新技术之间仍存在差距。具体来说，监测呼吸频率和呼吸模式的设备由于接线过多而给患者带来不便。该项目提出的平台可以显着缩小监测呼吸频率所需设备的尺寸。相同的技术可用于连续监测体温（包括核心体温）、心率、血压、摄氧量等，而无需更换电池。数据收集可以通过一个可以与智能手机通信的简单小型设备来实现。主要研究人员正在参加 NSF 支持的青年企业家和学者职业发展指导计划 (CAMP-YES) 以及中佛罗里达大学的研究和指导活动 (RAMA) 计划，这两个计划都旨在促进代表性不足的本科生的研究经验。该项目开发的资源将帮助主要研究人员通过招募学生参与这项研究来进一步为这些项目做出贡献。 该项目的主要目标是通过探索与超小型高效天线集成的极高品质因数 (Q) 压电高频谐振器来实现极小型无线无源传感器。在这项工作中，将首次展示压电超纳米晶金刚石平台中的回音壁模式声子腔，目标是在 1 GHz 左右的高频下实现高耦合因数和高品质因数。选择回音壁模式是为了避免锚损失（能量损失的主要来源），选择金刚石基板是为了最大限度地减少高频下内摩擦损失的影响。如此大的耦合和 Q 值可以实现尺寸极小的（1 厘米 x 1 厘米，包括天线）无线传感器，读取范围为几米。任务包括：1) 研究高频压电金刚石谐振器的损耗物理原理，2) 在薄膜金刚石压电平台中实现回音壁模式声子腔，3) 将声子腔与高效电小型天线集成以开发无源无线传感器。此类传感器可以比在类似频率下工作的其他无线传感器小几个数量级。该项目成功演示的极小型无线传感器将对医疗健康监测和诊断、环境监测和工业控制等广泛的遥感应用产生重大影响。

This project aims to explore and combine novel micro-scale resonator designs with extremely small antennas to build a wireless sensing platform that does not require power sources and takes advantage of the economy scale in delivering exceptional performance at very low price-points. This platform, once realized, is believed to make a significant impact on medical sensing paradigms by offering flexibility in remote and nonintrusive measurement of patients vital signs. Despite the tremendous technological progress made in the field of microelectronics during the past few decades, there exists a gap between the scale of sensing apparatus used in medical industry and the state-of-the-art in the field of miniaturized sensors. Specifically, the devices monitoring respiration rate and breathing pattern are inconvenient for the patients due to excessive wiring. The platform proposed in this project can significantly scale down the size of the equipment required for monitoring breathing rate. The same technology can be adapted for continuous monitoring of the temperature (including the core body temperature), the heart rate, blood pressure, oxygen intake, etc. without the need for changing the battery. The data collection can be achieved by a simple and small gadget that could communicate with smartphones. The principal investigators are participating in the NSF-supported Career Advancement Mentoring Program for Young Entrepreneur and Scholars Program (CAMP-YES) and the Research and Mentoring Activities (RAMA) program at the University of Central Florida, both of which promote research experience for underrepresented undergraduate students. The resources developed in this project will assist the principal investigators in furthering their contributions to these programs by recruiting students to engage in this research. The main objective of this project is to enable extremely-small wireless passive sensors by exploring exceptionally high quality factor (Q) piezoelectric-based high-frequency resonators integrated with ultra-small highly-efficient antennas. In this work, for the first time, whispering-gallery mode phononic cavities in a piezoelectric-on-ultrananocrystalline diamond platform will be demonstrated with the goal of achieving high coupling factor and high quality factor at high frequencies around 1 GHz. The whispering gallery mode is chosen to evade the anchor-loss (a major source of energy loss) and the diamond substrate is chosen to minimize the effect of internal friction losses at high frequencies. Such large values of coupling and Q could enable extremely-small size ( 1 cm x 1 cm including the antenna) wireless sensors with a readout range of a few meters. The tasks include: 1) Studying the physics of loss in high frequency piezoelectric-on-diamond resonators, 2) Implementation of whispering-gallery mode phononic cavities in the thin-film piezoelectric-on-diamond platform, 3) Integration of the phononic cavities with highly-efficient electrically-small antennas to develop passive wireless sensors. Such sensors can be orders of magnitude smaller than other wireless sensors operating at similar frequencies. Successful demonstration of extremely small wireless sensors targeted in this project will have a significant impact on a wide range of remote sensing applications including medical health monitoring and diagnosis, environmental monitoring, and industrial control.