CAREER:Active Nano-Acoustic Waveguide Matrix to Tackle Signal Processing Limits: Enabling Wideband and Nonreciprocal Integrated Communication Beyond the UHF

无线技术有望通过支持现代社会的基础设施（包括智能交通系统、物联网、智能制造和互联医疗保健）来彻底改变人类生活的各个方面。为了实现这样的革命，迫切需要极大地提高稀缺的无线电频谱资源及其使用效率。无线电频谱的有效获取对于从国家安全和公共安全到交通、广播和商业服务等多种社会需求至关重要，并且在经济持续增长中发挥着决定性作用。目前，对无线电频谱资源的无线访问受到可用信号处理硬件的限制，这些硬件仅在频谱的低端有效；因此，迫使当前的无线系统，如智能手机、平板电脑和全球定位系统 (GPS) 在非常有限的频率范围内运行（即超过 ~0.3-6 GHz）。如此小的频率范围已经过于拥挤，无法容纳新的无线用户或需要超高速数据通信的设施。此外，可用的硬件基本上无法在同一频带和同一时间同时进行数据传输和接收。因此，当前的无线系统被迫占用单独的频段来进行数据传输和接收；因此，频谱使用效率降低了一半。拟议的研究目标是通过开发单晶锗 (Ge) 变革性纳米声学技术来超越当前集成信号处理器的基本限制，该技术 1) 在整个超高频和极高频区域（即 3-300 GHz）高效运行，2) 通过根本不同的操作物理原理，实现在同一频段同时传输和接收数据；因此，频谱使用效率加倍。研究应包括 (1) 研究半导体中的纳米声波导，重点是单晶 Ge，用于超高频范围（UHF：0.3-3GHz）之外的宽带信号处理； （2）探索通过压电半导体纳米声波导中的声电效应对弹性信号进行主动电子放大的物理/科学； (3)超高频低损耗宽带信号处理器的设计与演示； (4) 芯片级不可逆信号处理器的工程，重点是隔离器和循环器。该项目与研究相结合，旨在通过教育套件和高中课程丰富新型纳米机电系统及其在日常生活中不可或缺的作用的社会知识，并通过女性和少数族裔学生的参与增强跨学科科学、技术、工程和数学（iSTEM）研究和职业的多样性。

Wireless technologies are poised to revolutionize all aspects of human life through enabling the infrastructures of a modern society, including intelligent transportation systems, internet of things, smart manufacturing, and connected healthcare. To enable such a revolution, there is a pressing need for tremendous enhancement of the scarce radio spectrum resources and their use efficiency. The effective access to radio spectrum is crucial for a diverse span of social needs ranging from national security and public safety to transportation, broadcasting and commercial services and plays a decisive role in continuous economic growth. The wireless access to radio spectrum resources is currently limited by the available signal processing hardware that are only efficient in the lower end of the spectrum; hence, forcing current wireless systems such as smart phones, tablets and global positioning systems (GPS) to operate in a very limited frequency range (i.e. over ~0.3-6 GHz). Such a small frequency range is already overcrowded and cannot accommodate new wireless users or amenities that require ultra-fast data communication. Furthermore, available hardware are fundamentally incapable of simultaneous data transmission and reception in the same frequency band and at the same time. Therefore, current wireless systems are forced to occupy separate bands for data transmission and reception; hence, cutting the efficiency of the spectrum use in half. The proposed research targets surpassing the fundamental limitations of current integrated signal processors through development of a transformative nano-acoustic technology in single crystal germanium (Ge) that 1) operates efficiently over the entire super- and extremely-high-frequency regimes (i.e. 3-300 GHz), and 2) enables simultaneous data transmission and reception in the same frequency band and at the same time, through fundamentally different operation physics; hence, doubling the spectrum use efficiency. Research shall consist of (1) investigation of nano-acoustic waveguides in semiconductors, with a focus on single crystal Ge, for wideband signal processing beyond the ultra-high-frequency regime (UHF: 0.3-3GHz); (2) exploration of the physics/science of active electronic amplification of elastic signals through the acoustoelectric effects in piezoelectric-semiconductor nano-acoustic waveguides; (3) design and demonstration of low-loss and wideband signal processors beyond the UHF; and (4) engineering of chip-scale nonreciprocal signal processors, with a focus on isolators and circulators. Integrated with the research, this project targets the enrichment of social knowledge on novel nano-electro-mechanical systems and their indispensable role in everyday life through educational kits and high-school curriculum, and enhancement of diversity in interdisciplinary Science, Technology, Engineering and Math (iSTEM) research and careers through involvement of female and minority students.