现代电磁技术的发展和革新离不开人们对新材料和新理论的探索。超表面，也叫人工电磁表面，突破了研究者们对电磁波调控的固有理念，从新的维度上实现了对电磁波的有效调控，是物理学、电磁学、材料学等交叉领域的前沿热点之一。目前的超表面大多基于金属或全介质结构单元，均为硬质基体，柔性差、电磁特性固定、成本较高。针对这些关键问题，本项目提出用生活中最常见的水来构建低成本、可调谐的电磁超表面的设想。通过理论分析、数值仿真与实验测试，深入分析水的亚波长谐振单元的散射机理和单元间耦合，探索利用水构建电磁超表面的设计方法和物理原理。进一步，研究水基超表面的可调谐电磁特性并探讨其在动态空间波束调控中的应用。本项目的顺利开展有助于开发具有生物亲和性的柔性、可重构电磁器件，在无线通信、传感、生物医学等诸多领域均具有广阔的应用前景。

The evolution of modern electromagnetic technologies, such as ultrafast wireless communications, relies on the development of new materials and novel theories. Metasurfaces, also known as artificially structured electromagnetic surfaces, offer unique properties that are not available in nature, broadening human being’s knowledge of manipulating electromagnetic beams. In general, much of the activity in this emerging field is based on metal/dielectric composites or all-dielectric units with certain configurations that resulting in extraordinary electromagnetic phenomena. These hard/solid matter based metasurfaces suffer from poor flexibility, fixed electromagnetic features, and high cost. Aiming to overcome these issues, in this proposal, we will focus on the design, fabrication, and characterization of water-based metasurfaces. We will first systematically study the resonant scattering mechanism as well as the mutual coupling of the water-based subwavelength units. We will then develop a design guidance of water-based metasurfaces and reveal the physics behind their extraordinary phenomena. The tunability of water-based metasurfaces and its application in configurable electromagnetic devices will further be investigated. The success of this project will result in the development of flexible, bio-friendly, and configurable electromagnetic devices, which could be extensively used for wireless communications, sensing, and biomedical applications.