一种新型短距通信信道及其电磁模式转换机理研究

The applications of evanescent modes in deep subwavelength images have been widely proved. However, because these modes can not propagate, their significance are failed to be recognized by wireless communication society for a long time. Recently, the development of the modes conversions and the far field information recovery techniques make the academia aware the importance of the evanescent modes in short range wireless communicsations. This project focuses on the study of the modes conversion mechnisms of the multi-antennas channels to improve the capacity of the short range wireless communication systems that lack of the traditional multipaths.1)we propose a new short range communication channel, i. e., to first use the superlens to amplify the evanescent modes containing the information, then convert the evanescent modes into the propagation modes using some specially distributed scatterers, e. g., periodic or random distributed structures, and subsequently, build a new form of the multipaths, that will improve the communication capacity; 2) change the shape and position parameters of the antennas, superlens and the scatterers, and then based on the surface currents and the fields obtained using the fast method MultiLevel Green's Function Interpolation Mehethod, analyze the propagation mechanism of the modes radiated by the multi-antennas calculate the channel admittance matrix and transfer matrix, analyze the law that these parameter affects the channel capacity.This project is not only benefitial to the theoretical research of the electromagnetic scattering, but also can be used in short range wireless communications.

倏逝模用于深亚波长成像早被证实，但因不能传播而长期没被通信界重视。近来发展的电磁模式转换和远场信息恢复技术使学术界意识到倏逝模在远场短距通信中的重要性。本项目针对短距无线通信中由于发射和接收装置相距较近，缺乏传统多径信道而使得信道容量变差这一问题，对多天线信道中的电磁模式转换机理进行建模研究。1）提出一种新型短距通信信道，即使用超级透镜对多天线辐射的倏逝模式进行放大，并通过一定分布(如周期分布或随机分布等)的散射体把放大的倏逝模转换成传播模，从而形成一种新多径形式，以提高通信容量；2）改变天线，超级透镜，以及散射体的形状和位置等，并基于使用快速算法-多层格林函数插值方法（MLGFIM）求解积分方程获得的表面电磁流和场分布，分析天线辐射的各模式的传播机理，计算该信道的输入导纳和信道矩阵，分析其对信道容量的影响规律，从而找到提高容量的方法。本课题兼具电磁散射研究的学术意义和无线通信应用价值。

倏逝模用于深亚波长成像早被证实，但因不能传播而长期没被通信界重视。近来发展的电磁模式转换和远场信息恢复技术使学术界意识到倏逝模在远场短距通信中的重要性。本项目针对电磁模式转换机理进行建模研究。1）利用人工表面等离子体的色散特性实现表面波到波束可控空间波的转换。2)利用局域性表面等离子体实现表面波模式到空间轨道角动量）的转换。3）利用新型人工电磁表面（超表面）的相位调控特性将表面波转换成圆极化辐射空间波。