Collaborative Research: Reconfigurable Intelligent Electromagnetic Surface Using Magnetic Shape Memory Polymers

通过平面孔径动态操纵电磁波的能力将导致可重构智能表面(RIS)的实现。这一愿景包括在蜂窝塔基站实施这种可重新配置的表面，以增加容量，并在室外和室内环境中为5G及以上无线系统的更多用户提供服务。此外，电磁波前的动态和任意操作是下一代无线通信、成像、全息照相、监视和传感应用的一种令人兴奋的通用工具。可重构性或可编程性是这种未来敏捷射频系统的重要特征。可重新配置的器件或电路(例如二极管和可变电容器)已被用于这种智能系统中以控制辐射图案、极化或工作频率。本项目首次研究了在RIS上使用可编程软材料的新方法。与最先进的技术相比，新方法提供了独特的优势。该项目是毫米波天线和阵列实验室(佐治亚理工学院电气和计算机工程学院)和软智能材料实验室(斯坦福大学机械工程系)之间的跨学科和协作努力。该项目的研究具有变革性，因为它挑战了已经应用于控制RIS和使用它们来重新配置那些无线系统的传统方法。这一新方法是基于一种可行的机械重构方法，该方法使用形状记忆聚合物和磁驱动。因此，与其他最先进的技术不同，每个单元内部不再需要二极管等半导体开关器件。这种全局重构方法的优势对于大型智能曲面来说变得更加重要。与使用二极管等半导体器件的传统重新配置方案不同，新架构采用独特的纯机械变形，不会受到与传统半导体器件相关的损耗和非线性的影响。在这个项目中，研究人员将使用具有磁性响应的软材料来驱动RIS在几十毫秒的外部磁场下的多模式机械形状重构。该项目预计将展示新方法相对于现有最先进技术的几个优势，包括磁激励实现的可编程性、线性、可扩展性、低操作电压、低损耗和多模式重新配置。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。

The ability to dynamically manipulate electromagnetic waves by a flat aperture will lead to the realization of reconfigurable intelligent surfaces (RIS). This vision includes implementing such reconfigurable surfaces at cell tower base stations to increase capacity and serve more users for 5G and beyond wireless systems in both outdoor and indoor settings. Moreover, dynamic and arbitrary manipulation of electromagnetic wavefronts is an exciting and versatile tool for next-generation wireless communication, imaging, holography, surveillance, and sensing applications. Reconfigurability or programmability is a vital feature of such future agile radio frequency systems. Reconfigurable devices or circuits (e.g., diodes and variable capacitors) have been used in such smart systems to control radiation pattern, polarization, or operating frequency. This project investigates a new approach of using programmable soft materials, for the first time, on RIS. The new approach offers unique advantages over the state-of-art technologies. This project is an interdisciplinary and collaborative effort between the mmWave Antennas and Arrays Laboratory (School of Electrical and Computer Engineering at Georgia Institute of Technology) and the Soft Intelligent Materials Laboratory (Department of Mechanical Engineering at Stanford University).The research of this project is transformative as it challenges the conventional methods that have been applied to control RIS and reconfigure those wireless systems using them. The new approach is based on a viable mechanical reconfiguration method using shape memory polymers and magnetic actuation. Thus, unlike other state-of-the-art technologies, semiconductor switching devices such as diodes are no longer needed inside each unit cell. The advantage of this global reconfiguration method becomes even more important for large intelligent surfaces. In contrast to traditional reconfiguration schemes that use semiconductor devices such as diodes, the new architecture utilizes a unique and purely mechanical deformation that does not suffer from loss and nonlinearity associated with traditional semiconductor devices. In this project, researchers will use magnetically responsive soft materials to drive the multimodal mechanical shape reconfigurations of the RIS under an external magnetic field with several tens of millitesla. The project is expected to demonstrate several advantages of the new approach over existing state-of-art technologies, including programmability enabled by magnetic excitation, linearity, scalability, low operating voltage, low loss, and multimodal reconfiguration.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.