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

该项目旨在探索和结合新颖的微型谐振器设计和极小的天线，以建立一个无线传感平台，不需要电源，并利用经济规模，以非常低的价格提供卓越的性能。这个平台一旦实现，通过提供对患者生命体征的远程和非侵入性测量的灵活性，被认为将对医学传感范例产生重大影响。尽管在过去的几十年里，微电子领域取得了巨大的技术进步，但医疗工业中使用的传感仪器的规模与微型化传感器领域的最先进水平之间仍存在差距。具体地说，由于布线过多，监测呼吸频率和呼吸模式的设备给患者带来不便。该项目中提出的平台可以显著缩小监测呼吸频率所需的设备的尺寸。同样的技术可以适用于连续监测温度(包括核心体温)、心率、血压、摄氧量等，而不需要更换电池。数据收集可以通过一个简单的、可以与智能手机通信的小工具来实现。主要研究人员参加了美国国家科学基金会支持的青年企业家和学者职业发展指导计划(CAMP-YES)和中佛罗里达大学的研究和指导活动(RAMA)计划，这两个计划都促进了未被充分代表的本科生的研究经验。在这个项目中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促进他们对这些项目的贡献。该项目的主要目标是通过探索集成超小型高效天线的极高品质因数(Q)压电基高频谐振器来实现超小型无线无源传感器。在这项工作中，将首次展示超非晶压电金刚石平台中的回声廊模声子腔，目标是在1 GHz左右的高频下实现高耦合系数和高品质因数。选择回音廊模式以避免锚点损失(能量损失的主要来源)，并选择金刚石衬底以最小化高频内耗损失的影响。如此大的耦合和Q值可以实现极小尺寸(1厘米x 1厘米，包括天线)的无线传感器，读出范围为几米。主要工作包括：1)研究高频金刚石压电谐振器的损耗物理；2)在金刚石上压电薄膜平台上实现耳廊模式声子腔；3)将声子腔与高效的电小天线相结合，研制无源无线传感器。这类传感器可以比以类似频率工作的其他无线传感器小几个数量级。该项目所针对的超小型无线传感器的成功演示将对包括医疗健康监测和诊断、环境监测和工业控制在内的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.