混响室的概率统计模型及其在随机电磁环境模拟中的应用

A reverberation chamber (RC) is an electrically large, multi-mode and shielded cavity with high Q value. The continuous rotation of the built-in stirrer continuously changes the boundary condition to change the distribution of the electromagnetic (EM) field inside the cavity, thereby generating a randomly varying field both in magnitude and direction. Because RCs can provide good shielding, low-cost, fast and thorough measurement, they are widely used in EM compatibility testing and measurement of multipath channel simulation in wireless communication. Although RCs have been successfully applied in the simulation of some Rayleigh and Rician environment, but research to simulate EM environment for more Rayleigh, Rician distribution and other ones that widely existed, such as lognormal distribution, Nakagami distribution, Weibull distribution and the interior of electrically large enclosure with aperture, has not been reported. Meanwhile, the research, development, testing and measurement of massive MIMO technologies in the upcoming 5G communication will also have greater demand for RCs and their simulation capability. For the above reasons, our project aims to theoretically explore RCs' capability to simulate random EM environments by constructing and analyzing probabilistic-statistical models which can give theoretical guidance on how to simulate various real EM environments, and to practically design and implement a RC that is convenient to be assembled and disassembled. According to the theoretical models, methods for different configurations of the RC will be proposed to realize more efficient simulation of more random EM environments, and to satisfy the growing demand for RCs in the fields of wireless communication and EM environment effect evaluation.

混响室(RC)是一个电大多模高Q值屏蔽腔体，通过内置搅拌器的连续旋转不断改变边界条件来改变腔内电磁场分布，从而产生大小和方向均随机变化的场。由于可以提供良好屏蔽、便宜、快速和彻底的测量，广泛用于电磁兼容测试和无线通信中多径信道模拟测量。尽管RC已经成功应用于部分瑞利和莱斯环境的模拟，但对于更多瑞利、莱斯环境和广泛存在的其他如对数正态分布、Nakagami分布、韦伯分布及电大开孔腔内部等电磁环境进行模拟的研究还未见报道。同时，未来5G通信中大规模MIMO技术的研发和测量测试还将会对RC及其模拟能力有更大需求。为此，本项目旨在通过构建和分析RC概率统计模型来从理论上发掘其模拟随机电磁环境的能力，并为如何模拟各种实际环境给出理论指引；设计并实现易拆装RC，在理论模型指引下，提出对RC进行不同配置的方法，实现对更多随机电磁环境的高效模拟，满足无线通信领域和电磁环境效应评估领域对RC日益增长的需求。

混响室是一个电大多模高Q值屏蔽腔体，通过内置搅拌器的连续旋转不断改变边界条件来改变腔内电磁场分布，从而产生大小和方向均随机变化的场。由于可以提供良好屏蔽、便宜、快速和彻底的测量，广泛用于电磁兼容测试和无线通信中多径信道模拟测量。尽管混响室已经成功应用于部分Rayleigh和Rician环境的模拟，但对于更多Rayleigh、Rician环境和广泛存在的其他如log-Normal分布、Nakagami分布、Weibull分布及电大开孔腔内部等电磁环境进行模拟的研究还未见报道。同时，未来5G通信中大规模MIMO技术的研发和测量测试还将会对混响室及其模拟能力有更大需求。为了实现混响室对更多随机电磁环境的高效模拟，本项目的主要研究内容包括：（1）混响室概率统计模型的建立；（2）混响室概率统计模型对若干随机电磁环境的数值仿真及分析；（3）易拆装混响室的设计、实现及随机电磁环境模拟的实验研究。通过研究，本项目获得如下重要结果：（1）从理论上发展了描述混响室内随机电磁环境的平面波积分（PWI）和随机模式展开（MEM）概率统计模型，构建了Rician场模型、累乘平面波模型和整合了多种模型的普适性模型，数值仿真研究证实了这些模型模拟不同随机电磁环境的能力。（2）提出了基于样本筛选的电磁衰落环境普适性模拟方法，结合混合搅拌技术，在混响室中实现了对满足Rician、Nakagami、log-Normal和Weibull等分布电磁衰落环境的模拟。（3）设计并构建了两种混响室，一种为易拆装混响室，另一种为可重构混响室。将自建混响室应用于随机电磁辐照效应测试、材料吸收截面测量和传输线耦合截面测量等。（4）对开孔腔体内和室外等实际电磁环境进行了大量计算或测量，由此获得了它们的统计特征。为了提高测量效率，开发了一款Android手机APP，将其和云存储技术相结合，初步实现了对室外电磁环境的高效测量。这些结果的意义在于：本项目通过构建和分析混响室概率统计模型，从理论上进一步发掘了混响室模拟随机电磁环境的能力；设计并实现了易拆装混响室，在理论模型指引下提出了对混响室进行不同配置的方法，实现了对更多随机电磁环境的经济和高效模拟，较好地满足了无线通信领域和电磁环境效应评估领域对混响室日益增长的需求。