非均匀磁化等离子鞘套包覆电大平台附近天线受扰辐射特性研究

The plasma sheath formed during the flight process of hypersonic vehicle in near space cuts off the communication of aircraft for a long time by affecting the transmission of radio signals and the radiation characteristics of antennas loaded by aircraft. Analysis on the radiation characteristics and the performance istortion of the antenna near the platform around the plasma sheath is an important research topic. However, due to the complex electromagnetic structure of the plasma and the large electrical size of the aircraft platform, study of this.problem is historically challenging. In this proposal, a fast-forward model for the calculation of electromagnetic response in magnetized plasma is derived. We propose to develop a hybrid method according to Huygens principle, combining with the fast-forward model. This systematic method is proposed to calculate and analyze the disturbed radiation pattern of the complex antenna near the electrical large platform around the magnetized plasma. The forward model has significant impact to understand the transmission mechanism of electromagnetic wave in plasma sheath. At the same time, the analysis of the antenna radiation characteristics under the influence of both platform and sheath are used to summarize the relationship between the radiation performance of the antenna and other factors, such as the working frequency, inhomogeneous plasma sheath electron collision frequency, electron density and so on. The research method proposed by this.project combines advanced technology and theory, and the results have great research value and potential applications.

临近空间高超声速飞行器飞行过程中所形成的“等离子体鞘套”，通过影响无线信号的传输和飞行器所加载天线的辐射特性，导致飞行器通信的长时间中断。“等离子体鞘套”覆盖下电大平台附近天线的辐射特性和性能畸变分析是一个重要的前沿课题。但由于等离子体电磁结构复杂、飞行器平台电尺寸巨大的特点，至今未形成一套完整成熟的理论体系和有效的研究方法。本项目拟推导建立磁化等离子体中电磁响应计算的快速正演模型，结合高低频混合方法建立基于惠更斯原理的等离子体覆盖下电大平台附近复杂天线受扰辐射特性分析的一体化数值计算方法，探索等离子体鞘套中的电磁波传播机理，分析天线在同时受到平台和鞘套两者作用下的受扰辐射特性，掌握天线辐射性能的影响因素和规律，最终形成一套兼顾效率和精度的数字化分析方法。本项目申请所提出的这一研究方法将先进技术与理论相结合，所取得的成果具有较大的研究价值和应用潜力。

课题着眼于磁化等离子体对电大平台附近天线受扰辐射特性分析的迫切需要，在电磁理论的基础上借助计算机仿真的方式，推导建立磁化等离子体中电磁响应求解的正演模型，探索电磁波在等离子体中的传播机理，进一步开展天线在同时受到平台和鞘套两者作用时受扰辐射特性分析的一体化电磁计算方法研究。项目主要完成以下研究内容：1) 根据各向异性介质中的谱域电磁场方程，推导分层各向异性介质中的广义传输矩阵(SMM)，建立磁化等离子体分层各向异性等效介质模型中电磁响应求解的半解析化方法；2) 通过等效电路参数建立了两层水平层状结构的等效Debye模型，并进一步通过迭代方式建立多层水平层状结构的等效Debye模型，获得层状结构模型的等效电参数频散特性解析解，为不同频段下等离子体鞘套分层等效模型中各层电学参数的确定建立了理论基础；3) 基于惠更斯原理的 ECM-UTD-SMM 迭代修正模型，建立一种兼顾计算精度及效率的计算方法，充分考虑了电大平台、鞘套及天线三者之间的相互作用，分析平台和鞘套同时作用于天线的受扰辐射特性，实现了在有限的计算机资源下，所建立的天线，飞行器，等离子体鞘套三者一体化研究方法能够准确分析飞行器上加载天线的受扰辐射特性，算法兼顾精度和效率，对于准确评价“黑障”现象的影响因素具有重要的工程应用价值。

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