CAREER: RF Co-Designated Fully-Directional Antenna Interfaces for Dynamic and Efficient Spectrum Access

无线通信系统正日益覆盖我们生活的方方面面，包括在移动电话、医疗服务、自动驾驶和太空探索中的应用。虽然无线技术正在显著改变我们的社会利用它们促进公共安全和经济增长的方式，但它们也导致了无线电频谱极度拥挤。为了应对这一挑战，目前正在考虑针对毫米波频率（30-100 GHz）的新分配、全双工频谱使用以及在未充分利用或未经许可的频段运行的创新频谱共享解决方案。虽然使用更高的频率可以保证更宽的带宽和更高的数据速率，但这些频率不适合远程通信，并且需要昂贵的射频（RF）硬件解决方案。这项研究的主要目标是解决国家对频谱可持续性、无处不在的连接和提高低于6 GHz频率的国家安全的需求，其中频谱更加拥挤。特别是，该职业发展项目将重点关注射频共同设计的全方向天线接口，通过以下方式为高效频谱共享铺平道路：i)全双工操作，ii)未充分利用和未授权频段的动态接入，以及iii)抑制干扰。拟议的研究承诺在频谱共享方面进行革命性的改进，并允许在高性能和高密度无线技术至关重要的领域（包括下一代蜂窝通信、物联网和公共安全）提供新功能。该项目更广泛的教育目标包括培养与下一代射频系统相关领域的本科生和研究生，通过新的课程模块和可调谐滤波器设计技术的新课程加强科罗拉多大学博尔德分校的电气工程（EE）课程。外联活动的重点将是扩大学生对社会教育的参与，并将高等教育推广到传统上代表性不足的人群，包括社区大学学生、退伍军人和妇女。本提案的主要目标是通过基于射频协同设计的全方向天线接口的新的射频前端设计和集成概念，研究和建立高度小型化和高度可重构的射频前端的理论基础，该接口可在现场编程，并实现动态和高效的频谱接入。特别是，所提出的研究将为以下方面奠定基础：i)全方向滤波器的合成和设计方法；ii)具有协同信号处理能力的射频组件；iii)射频前端链的多级传递函数可调性。研究的一个具体重点将是了解时空调制和非互反滤波器设计的基本限制，并确定各种高影响应用的权衡，范围从蜂窝到军事和空间通信系统。将开发促进多层传递函数可重构性的调谐方法，并研究其在高效频谱接入方面的有效性。此外，还将系统地研究射频协同设计天线接口的尺寸和性能权衡。所提出的技术将改变全双工无线电在频谱拥挤环境中的实现和运行方式，并将为具有多功能和多标准能力的通用射频前端铺平道路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Wireless communication systems are increasingly covering every facet of our lives, including their use in mobile phones, healthcare delivery, autonomous driving, and space exploration. While wireless technologies are significantly changing the way our society is exploiting them for public safety and economic growth, they have resulted in an extremely congested radio spectrum. To address this challenge, innovative spectrum sharing solutions targeting new allocations at millimeter-wave frequencies (30-100 GHz), full-duplex spectrum usage and operation in under-utilized or unlicensed frequency bands are currently being considered. While the use of higher frequencies promises wider bandwidths and higher data-rates, these frequencies are not suitable for long-range communications and require expensive radio frequency (RF) hardware solutions. The main goal of this research is to address the nation's needs for spectrum sustainability, ubiquitous connectivity and increased national security for frequencies lower than 6 GHz, where the spectrum is more congested. In particular, this career development project will focus on RF co-designed fully-directional antenna interfaces that pave the way to efficient spectrum sharing through: i) full-duplex operation, ii) dynamic access of under-utilized and unlicensed frequency bands and iii) suppression of interference. The proposed research promises revolutionary improvements in spectrum sharing and allows for new capabilities in areas in which high-performance and high-density wireless technologies are of paramount importance, including next generation cellular communications, internet of things, and public safety. The program's broader educational goals include training of undergraduate and graduate students in areas related to next-generation RF systems, enhancing the Electrical Engineering (EE) curriculum at the University of Colorado Boulder with new class modules and a new class on tunable filter design techniques. The outreach activities will focus on broadening the participation of students in EE and promote higher education to traditionally under-represented populations including community-college students, veterans and women.The major objective of this proposal is to investigate and establish the theoretical foundations for highly-miniaturized and highly-reconfigurable RF front-ends through a new RF front-end design and integration concept based on RF co-designed fully-directional antenna interfaces that are in-field programmable and enable dynamic and efficient spectrum access. In particular, the proposed research will set the basic foundations for: i) fully-directional filter synthesis and design methods, ii) RF components with collocated signal processing capabilities and iii) multi-level transfer function tunability of the RF front-end chain. A specific focus of the research will be to understand the fundamental limits of spatio-temporal modulation and non-reciprocal filter design and determine trade-offs for various high-impact applications ranging for cellular to military and space communication systems. Tuning methods that facilitate multiple levels of transfer function reconfigurability will be developed, and their effectiveness in terms of efficient spectrum access will be studied. Furthermore, the trade-offs of size and performance of RF co-designed antenna interfaces will be systematically investigated. The proposed techniques will transform the way full-duplex radios are implemented and operated in spectrally-congested environments and will pave the way to generalized RF front-ends with multi-functional and multi-standard capabilities.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.