时间反演超分辨率亚波长阵列的建模仿真和量化设计理论研究

In modern high-capacity and high-speed wireless communication systems, the design of multi-antennas faces the problem of how to build intensive independent channels in limited space. Based on the the spatial and temporal focusing and spatial super-resolution focusing characteristics of time reversal (TR) electromagnetic waves, this project aims to realize the sub-wavelength antenna arrays with far-field super-resolution ability of TR electromagnetic waves, and investigate the methods of computational modeling and quantitative designing efficiently. Firstly, the internal mechanism of transmission, radiation and evanescence modes in sub-wavelength micro-structures is studied, and the theoretical model from evanescence modes with near-field super-resolution information to transmission and radiation modes will be established. Secondly, in the local communication space including sub-wavelength arrays, the efficient simulation algorithms for multi-scale and complex TR electromagnetic problems are studied to realize computational modeling. Thirdly, based on the model from evanescence modes to transmission and radiation modes, the efficient optimization theory for sub-wavelength array design is developed to present the far-field super-resolution characteristics. At the same time, a prototype experimental system to demonstrate our theory and design is constructed. The research of this project can establish important theoretical and technological foundations for future developments of super-resolution application systems for TR electromagnetic waves.

现代大容量高速无线通信系统中，多天线的设计面临如何在有限空间构建密集独立通道的难题。基于时间反演（time reversal，TR）电磁波的时-空聚焦和空间超分辨率聚焦特性，本项目旨在实现具有TR电磁波远场超分辨率能力的亚波长微结构阵列天线，并探索其高效、准确的可计算分析手段和量化设计理论。首先，研究亚波长微结构的传输模、辐射模和凋落模的内在机理，建立将携带近场超分辨率信息的凋落模转化为传输模和辐射模的理论模型，进而实现远场超分辨率特性；其次，在含亚波长阵列的局部通信环境下，研究多尺度复杂TR电磁波问题的高效仿真方法，实现其可计算建模；然后，基于凋落模转化为传输模和辐射模的模型，研究实现远场高分辨率特性的亚波长阵列的高效优化理论，实现其可量化设计，并完成原理性实验系统的构建和实验验证。项目的研究将为发展新型TR电磁波超分辨率应用系统奠定坚实的理论与技术基础。

基于时间反演（time reversal，TR）电磁波的时-空聚焦和空间超分辨率聚焦特性，本项目实现具有TR电磁波远场超分辨率能力的亚波长微结构阵列天线，并探索了其高效、准确的可计算分析手段和量化设计理论。首先，研究亚波长微结构的传输模、辐射模和凋落模的内在机理，建立了将携带近场超分辨率信息的凋落模转化为传输模和辐射模的理论模型，进而实现远场超分辨率特性。研究了影响TR电磁波超分辨率聚焦的因素，包含时间反演镜放置位置、时间反演镜个数、亚波长阵列有无金属丝加载、加载金属丝阵列结构是否均匀分布等；其次，在含亚波长阵列的局部通信环境下，研究了多尺度复杂TR电磁波问题的高效仿真方法，实现其可计算建模。提出了无条件稳定的Newmark-Beta时域有限差分（finite-difference time-domain，FDTD）法、深入研究了区域分解Laguerre-FDTD法、深入研究了基于空间滤波技术的亚网格FDTD法、提出了区域分解的CN-FDTD法、将射线追踪法成功地应用于TR时空同步聚焦仿真、采用近场辅助源实现了TR超分辨率聚焦；然后，基于凋落模转化为传输模和辐射模的模型，研究了实现远场高分辨率特性的亚波长阵列的高效优化理论，实现其可量化设计。在探索小型化的模式转换结构的基础上，实现亚波长微结构阵列“远场有效辐射和超分辨率聚焦”的双重目标，设计了两款微结构天线阵列：蚀刻十字结构的TR亚波长阵列天线和TR超分辨率聚焦层叠MIMO阵列天线，并完成原理性实验系统的构建和实验验证。项目的研究将为发展新型TR电磁波超分辨率应用系统奠定坚实的理论与技术基础。