Breaking the Barrier for Acoustic Resonators: High Performance Filters at Millimeter Waves

毫米波通信标准旨在通过促进增强现实和虚拟现实、无人驾驶飞行器和自动驾驶汽车、远程健康和基础设施监测以及更广泛的物联网的高速数据链接，为社会带来革命性的变化。正在商业化的毫米波系统不依赖于天线单元的滤波。可以预见的是，随着部署的系统数量的增加，干扰以及缺乏滤波将成为这些通信系统的瓶颈，导致基带电子设备的巨大功耗。随着更多毫米波系统的部署，频谱变得拥堵，处理干扰信号将需要更高的功率消耗。通过在天线单元处进行毫米波滤波来消除干扰的需求将成为进一步部署这些网络的根本瓶颈。以片上/便携式/可穿戴设备所需的形状因数设计和实现这些频率的带通滤波器尤其具有挑战性。这项研究项目建议使用声学元件直接在每个天线元件上进行锐化滤波。如果成功，该项目将产生比本文提出的特定毫米波应用更广泛的影响。通过克服与毫米波声谐振器设计和合成相关的基本挑战，这项研究将设计一个通用的谐振器平台，用于研究与量子信息科学、计算和传感相关的其他现象。将声谐振器的工作范围扩展到毫米波频率时，伴随着与能否以低损耗和合适的阻抗水平在如此高的频率下工作的基本问题。在毫米波获得高性能是声学设备的一个基本障碍。要回答这些问题，就需要对材料、纳米制造工艺和谐振器设计进行调查，这些设计挑战了声学设备的最先进水平。这项工作的智慧价值在于：研究毫米波悬浮结构薄膜中的基本减振机制；设计创新的谐振器设计，在保持谐振器特性阻抗匹配的同时最大限度地减少损耗；以及开发能够以高成品率使纳米级特征与微米级结构共存的纳米制造方法。这个项目的最终应用目标是设计一种工作在毫米波的带通滤波器，该滤波器使用以传统梯形结构布置的声谐振器集合。该项目还在研究各种新技术，用于产生两个邻近频率的谐振器和实时调谐滤波器带宽。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Communication standards at millimeter waves are meant to revolutionize society by facilitating high speed data links for augmented and virtual reality, unmanned air vehicles and self-driving cars, remote health and infrastructure monitoring, and the broader Internet of Things. The millimeter wave systems that are being commercialized do not rely on filtering at the antenna element. It is predictable that as the number of deployed systems will increase, interferers and hence the lack of filtering will be a bottleneck for these communication systems, resulting in large power consumption by the baseband electronics. As more millimeter wave systems are deployed, and the spectrum is getting congested, increase power consumption will be required to handle interfering signals. The needs to eliminate interferers through mm-wave filtering at the antenna element will become a fundamental bottleneck to further deployment of these networks. The design and implementation of bandpass filters at these frequencies in the form factors required by on-chip/portable/wearable devices is particularly challenging. This research project proposes to use acoustic elements to deliver sharp filtering directly at each antenna element. If successful, this project will have broader impacts beyond the specific millimeter wave applications proposed herein. By overcoming the fundamental challenges associated with the design and synthesis of millimeter wave acoustic resonators, the research effort will devise a general resonator platform for investigating other phenomena associated with quantum information science, computing and sensing.Extending the range of operation of acoustic resonators to millimeter wave frequencies comes with fundamental questions related to the ability to operate at such high frequency with low loss and appropriate impedance levels. Attaining high performance at millimeter waves is a fundamental barrier for acoustic devices. Answering these questions calls for investigations into materials, nanofabrication processes and resonator designs that challenge the state-of-the-art in acoustic devices. The intellectual merit of this work consists in: investigating fundamental damping mechanisms in thin films of suspended structures at millimeter waves; devising innovative resonator designs that minimize damping while preserving resonator characteristic impedance matching; and developing nanofabrication methods that enable the co-existence of nanoscale features with micron-scale structures with high yields. The ultimate applied goal of this project is to devise a bandpass filter operating at millimeter waves using an ensemble of acoustic resonators arranged in a conventional ladder configuration. This project is also investigating various novel techniques for generating two nearby-frequency resonators and for real-time tuning of the filter bandwidth.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.