Theory and application of reconfigurable intelligent surfaces with integrated sensing

实现高数据速率的不间断无线通信的一个主要挑战是传播环境造成的损耗，例如建筑物对信号的阻塞或信号在不同表面的绕射。为了解决这些问题，提出了使用可重构智能曲面(RIS)的技术。RIS可以将反射信号重定向到目标用户，从而避免信号阻塞、减轻干扰或提高安全性。然而，设计期望的传播环境需要关于重要参数的知识，例如用户或发射机的方向在RIS处可用。为了满足这一需求，本项目将开发一种新型的混合可重构智能曲面(HRIS)。HRIS将被设计成感测整个表面上的入射波，推断相关信息，如用户和发射器的方向，并相应地重新配置它们的反射模式。通过开发HRIS，该项目为实现真正智能和自主的传播环境铺平了道路。该项目还研究了HRIS能够以高空间分辨率感知环境的其他机会，例如为背景感知房屋和建筑成像对象或威胁检测。该研究项目还有一个全面的教育计划，旨在让研究生和本科生参与设计变形表面和HRIS，开发压缩传感技术，并设计智能电磁环境。该项目还包括几个本科生主导的项目，他们将学习使用HRIS来跟踪设备，并为它们提供用于无线能量传输(WPT)的聚焦波束。由此产生的自适应WPT演示将用于关于电磁研究和无线通信和传感的新趋势的互动研讨会，以及在外联活动中使用。本研究项目将概述HRIS的设计，并通过实验演示其在典型无线通信环境中的效用。因此，它将做出创新的贡献，包括1)设计允许可重新配置的反射和感测入射波的新的亚表面，2)开发和实验验证仅使用几个接收单元就具有高空间分辨率的传播环境的压缩感测的新算法，3)智能自适应通信链路，其中HRIS检测发射机和用户并相应地变换其反射图案，和4)开发和实验验证新的成像配置，其中分散的无线通信信号(机会信号)由HRIS收集并处理以检索反射率地图。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。

One major challenge in achieving uninterrupted wireless communications with high data rate is the loss due to propagation environment, such as signal blockage by buildings or signal diffraction by various surfaces. To circumvent these issues, the technique of using reconfigurable intelligent surfaces (RIS) has been proposed. RIS can redirect reflected signals toward intended users, thus avoiding signal blockage, mitigating interference, or increasing security. Engineering the desired propagation environment, however, requires knowledge about important parameters such as the directions of the users or transmitters to be available at the RIS. To address this need, this project will develop a new type of hybrid reconfigurable intelligent surfaces (HRIS). The HRIS will be designed to sense the incident waves on the entire surface, deduce relevant information, such as the directions of users and transmitters, and reconfigure their reflection patterns accordingly. By developing the HRIS, this project paves the way for the implementation of a truly smart and autonomous propagation environment. This project also examines other opportunities that can be enabled by the HRIS to sense the environment with high spatial resolution, such as imaging objects for context-aware homes and buildings or threat detection. The research project is complemented by a comprehensive educational plan to engage graduate and undergraduate students in designing metasurfaces and HRIS, developing compressive sensing techniques, and devising intelligent electromagnetic environments. This project also includes several undergraduate-led efforts where they will learn to use the HRIS to track devices and provide them with focused beams for wireless power transfer (WPT). The resulting adaptive WPT demonstrations will be used in interactive workshops on topics of electromagnetic research and emerging trends in wireless communications and sensing, as well as at outreach events.This research project will outline the design of HRIS and experimentally demonstrate their utility in typical wireless communications settings. It will thus make innovative contributions including 1) the design of a novel metasurface that allows for reconfigurable reflection and sensing of the incident wave, 2) the development and experimental validation of novel algorithms for compressive sensing of the propagation environment with high spatial resolution using only a few receiving units, 3) a smart adaptive communications link where the HRIS detects the transmitter and users and transform its reflection patterns accordingly, and 4) development and experimental validation of novel imaging configurations where the scattered wireless communications signals (signals of opportunities) are collected by the HRIS and processed to retrieve reflectivity maps.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.