高性能时域有限差分算法及新型圆极化微带天线设计
发布时间：2018-12-11 20:42
【摘要】：为了满足通信、雷达和导航应用的需求,现代大型舰船平台上通常安装着各种电子系统。这些电子系统的近场互耦会导致复杂的电磁环境效应,使得系统整体性能变差。另外,这些电子系统和舰船平台对外来电磁干扰(Electromagnetic Interference,EMI)非常敏感,严重时会导致系统失效。解决这些电大尺寸、多尺度的平台级电磁兼容(Electromagnetic Compatibility,EMC)问题需要高效、精确的数值计算方法。时域有限差分算法(Finite-Difference Time-Domain,FDTD)已经被大量应用于解决这些问题,然而由于FDTD的时间步长受限于空间网格大小,传统的FDTD方法在求解这类问题时计算效率受到严重限制。本文针对大型舰船平台上的电磁兼容问题,拓展了单步无条件稳定时域有限差分算法(Leapfrog Alternately-Direction-Implicit FDTD,ADI-FDTD),应用于舰船平台上细线天线的精确仿真。本论文主要内容和创新点如下:(1)介绍了传统FDTD和隐式FDTD算法中效率最高的Leapfrog ADI-FDTD的基本迭代方程和Yee网格剖分,并分析了算法的数值色散特性和稳定性条件。其次介绍了卷积完美匹配层(Convolutional Perfectly Matched Layer,CPML)和引入各种不同激励源的方法。最后介绍了 FDTD中经典的细导线模型。(2)将FDTD中经典的细导线算法拓展到Leapfrog ADI-FDTD中,适用于仿真大型舰船平台上的单极子细线天线。基于VonNeumann方法和大量数值实验,半解析地证明了该算法的无条件稳定性。将该算法应用于仿真大型舰船平台上的电磁兼容问题,包括计算天线之间近场耦合效应(S参数)和天线远场辐射方向图,以及有外来平面波辐照下天线端口感应的电压和舰船平台表面电流密度分布。(3)设计了一种双频双圆极化偏心圆环微带天线,对天线的工作机理进行了深入探究,并研究了不同结构参数对天线性能的影响。提出了一个集总元件等效电路以深入理解天线的工作机理,并给出一组经验公式和设计指导以简化设计流程。最后制作了天线实物并进行实验测量,结果与仿真吻合较好。
[Abstract]:In order to meet the needs of communication, radar and navigation applications, modern large ship platforms are usually equipped with various electronic systems. The near field mutual coupling of these electronic systems will lead to complex electromagnetic environmental effects, which makes the overall performance of the system worse. In addition, these electronic systems and ship platforms are sensitive to external electromagnetic interference (Electromagnetic Interference,EMI), which can lead to system failure. Solving these electrically large scale and multi-scale platform-level electromagnetic compatibility (Electromagnetic Compatibility,EMC) problems requires efficient and accurate numerical methods. Finite-Difference Time-Domain (Finite-Difference Time-Domain,FDTD) algorithm has been widely used to solve these problems. However, the time step size of FDTD is limited by the size of space mesh. The computational efficiency of the traditional FDTD method is severely limited in solving this kind of problems. In order to solve the electromagnetic compatibility problem on large ship platforms, this paper extends the single step unconditionally stable finite difference time-domain (Leapfrog Alternately-Direction-Implicit FDTD,ADI-FDTD) algorithm, which is applied to the precise simulation of thin wire antennas on ship platforms. The main contents and innovations of this thesis are as follows: (1) the basic iterative equations and Yee mesh generation of the most efficient Leapfrog ADI-FDTD in the traditional FDTD and implicit FDTD algorithms are introduced, and the numerical dispersion characteristics and stability conditions of the algorithm are analyzed. Secondly, the convolution perfectly matched layer (Convolutional Perfectly Matched Layer,CPML) and the methods of introducing different excitation sources are introduced. Finally, the classical thin wire model in FDTD is introduced. (2) the classical thin wire algorithm in FDTD is extended to Leapfrog ADI-FDTD, which is suitable for simulating monopole thin wire antenna on large ship platform. Based on the VonNeumann method and a large number of numerical experiments, the unconditional stability of the algorithm is semi-analytically proved. The algorithm is applied to the simulation of electromagnetic compatibility problems on large ship platforms, including the calculation of near-field coupling effects (S parameters) between antennas and the far-field radiation pattern of antennas. The voltage induced by external plane waves and the distribution of current density on the surface of the ship's platform are obtained. (3) A dual-frequency double-circularly polarized eccentric annular microstrip antenna is designed, and the working mechanism of the antenna is deeply investigated. The effect of different structure parameters on antenna performance is also studied. An equivalent circuit of lumped elements is proposed to understand the working mechanism of antenna. A set of empirical formulas and design instructions are given to simplify the design process. Finally, the antenna is made and measured, and the results are in good agreement with the simulation.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN822
，
本文编号：2373188
[Abstract]:In order to meet the needs of communication, radar and navigation applications, modern large ship platforms are usually equipped with various electronic systems. The near field mutual coupling of these electronic systems will lead to complex electromagnetic environmental effects, which makes the overall performance of the system worse. In addition, these electronic systems and ship platforms are sensitive to external electromagnetic interference (Electromagnetic Interference,EMI), which can lead to system failure. Solving these electrically large scale and multi-scale platform-level electromagnetic compatibility (Electromagnetic Compatibility,EMC) problems requires efficient and accurate numerical methods. Finite-Difference Time-Domain (Finite-Difference Time-Domain,FDTD) algorithm has been widely used to solve these problems. However, the time step size of FDTD is limited by the size of space mesh. The computational efficiency of the traditional FDTD method is severely limited in solving this kind of problems. In order to solve the electromagnetic compatibility problem on large ship platforms, this paper extends the single step unconditionally stable finite difference time-domain (Leapfrog Alternately-Direction-Implicit FDTD,ADI-FDTD) algorithm, which is applied to the precise simulation of thin wire antennas on ship platforms. The main contents and innovations of this thesis are as follows: (1) the basic iterative equations and Yee mesh generation of the most efficient Leapfrog ADI-FDTD in the traditional FDTD and implicit FDTD algorithms are introduced, and the numerical dispersion characteristics and stability conditions of the algorithm are analyzed. Secondly, the convolution perfectly matched layer (Convolutional Perfectly Matched Layer,CPML) and the methods of introducing different excitation sources are introduced. Finally, the classical thin wire model in FDTD is introduced. (2) the classical thin wire algorithm in FDTD is extended to Leapfrog ADI-FDTD, which is suitable for simulating monopole thin wire antenna on large ship platform. Based on the VonNeumann method and a large number of numerical experiments, the unconditional stability of the algorithm is semi-analytically proved. The algorithm is applied to the simulation of electromagnetic compatibility problems on large ship platforms, including the calculation of near-field coupling effects (S parameters) between antennas and the far-field radiation pattern of antennas. The voltage induced by external plane waves and the distribution of current density on the surface of the ship's platform are obtained. (3) A dual-frequency double-circularly polarized eccentric annular microstrip antenna is designed, and the working mechanism of the antenna is deeply investigated. The effect of different structure parameters on antenna performance is also studied. An equivalent circuit of lumped elements is proposed to understand the working mechanism of antenna. A set of empirical formulas and design instructions are given to simplify the design process. Finally, the antenna is made and measured, and the results are in good agreement with the simulation.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN822
，
本文编号：2373188
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