Collaborative Research: NeTS: Medium: Scalable Metasurface Array for mmWave Communication and Sensing

毫米波(毫米波)技术在5G通信和雷达传感应用中都显示出令人兴奋的前景。然而，MmWave的有限覆盖范围仍然是其在实践中可用性的主要挑战。该项目的目标是利用毫米波通信/传感系统和可打印材料/电子产品的协同创新，以克服毫米波信号的内在局限性。PI团队探索了超大型和超宽带变形表面阵列的设计，以扩大毫米波覆盖范围并优化相关的性能权衡。项目成果可能会为毫米波网络的设计提供参考，影响Beyond-5G(B5G)标准化，并推动许多B5G应用，特别是在具有挑战性的毫米波车载网络和汽车传感领域。该项目还可以通过以极低的成本提高5G毫米波的覆盖率和可靠性来产生重大的经济影响。该项目的影响将通过吸引不同的学生研究人员和工业合作伙伴，以及通过传播用于先进毫米波设备的开源实验硬件和低成本制造工作流程来进一步扩大。这项拟议的研究结合了新的可打印材料/电子设备，以促进毫米波超表面反射器领域的发展。虽然有源和无源的介面在电磁研究中已经得到了广泛的探索，但它们在大小、带宽方面都是有限的，并且大多用于单个链路。有源金属表面需要电源、高频元件、高精度衬底和制造工艺，以及与现有器件协调的单独控制通道，因此成本和复杂性都很高。另一方面，由于缺乏可重构性，被动变形表面反射器通常被认为是劣质的，仅适用于静态场景。此外，最先进的主动/被动亚表面仅限于厘米级，但实际部署需要在尺寸上达到米级(数百个波长)，这导致了许多挑战，如近场效应和频率选择性导致的严重光束失真。为了应对这些挑战，PI团队提出了3项研究重点：(1)设计新的波束合成模型，以实现超大型元表面，以及采用新技术逐步重新配置无源元表面阵列(PMA)，以扩大角度覆盖、波束形成增益、支持移动性，并避免附近基站之间的干扰；(2)设计新机制，利用PMA作为无源“编码器”，解决毫米波传感中覆盖、分辨率和维度的权衡；(3)探索基于石墨烯的元表面结构，以扩展毫米波联合通信，并超越传统射频硬件的带宽限制。这项拟议的研究将产生各种社区工具包和可重复制造的工作流程，用于通过3D打印或模具打印创建低成本的毫米波超表面。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。

Millimeter-wave (mmWave) technologies are demonstrating exciting prospects in both 5G communications and radar sensing applications. However, the limited coverage of mmWave remains a major challenge to its usability in practice. The objective of this project is to harness synergistic innovations in mmWave communication/sensing systems and printable materials/electronics to overcome the intrinsic limitations of mmWave signals. The PI team explores the design of an ultra-large and ultra-wideband metasurface array to expand mmWave coverage and optimize the associated performance tradeoffs. The project outcome will likely inform the design of mmWave networks, influence the beyond-5G (B5G) standardization, and advance many B5G applications, especially in the challenging mmWave vehicular networking and automotive sensing domains. The project can also generate substantial economic impacts by boosting the 5G mmWave coverage and reliability at signifcantly low cost. The project impact will be further extended by engaging a diverse group of student researchers and industrial partners, and by disseminating open-source experimental hardware and low-cost fabrication workflows for advanced mmWave devices. The proposed research incorporates novel printable materials/electronics to advance the field of mmWave metasurface reflectors. Although active and passive metasurfaces have been extensively explored in electromagnetic research, they are limited in size, bandwidth, and mostly employed for a single link. Active metasurfaces bear a high cost and complexity as they need power sources, high-frequency components, high-precision substrate and fabrication processes, and a separate control channel to coordinate with existing devices. On the other hand, passive metasurface reflectors are often deemed inferior and suitable only for static scenarios due to lack of reconfigurability. In addition, state-of-the-art active/passive metasurfaces are limited to centimeter-scale, yet practical deployment entails meter-level (hundreds of wavelengths) in dimension, which induces non-trivial challenges such as severe beam distortion due to near-field effects and frequency-selectivity. To address these challenges, the PI team proposes 3 research thrusts: (1) Designing new beam synthesis models to enable ultra-large metasurfaces, and new techniques to incrementally reconfigure a passive metasurface array (PMA), so as to expand the angular coverage, beamforming gain, support mobility, and to avoid interference between nearby base stations; (2) Designing new mechanisms that leverage the PMA as a passive "encoder" to address the coverage-resolution-dimension tradeoff in mmWave sensing; (3) Exploring graphene-based metasurface structures to scale mmWave joint communication and sensing beyond the bandwidth limit of traditional RF hardware. The proposed research will lead to various community toolsets and reproducible fabrication workflows for creating low-cost mmWave metasurfaces through 3D printing or mold imprinting.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.