基于矩量法的介质和微带结构研究

发布时间：2018-05-16 19:07

本文选题：矩量法 + 积分方程　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：现今通信行业迅速发展,对设备提出了小型化,轻质量,高效率等要求,微带结构因具备这些独有的特性而得到广泛应用,已经深入到航空、航天通信等领域,所以对微带结构的研究变得愈加重要,分析微带结构的电磁散射与辐射特性也成为研究领域的一个不可忽视的课题。在微带结构的研究中,常用的方法有时域有限差分法(FDTD)和矩量法(MOM)。时域有限差分法,它编程简单而且通用性好,可以一次性地计算全频带的响应,但为了达到精度要求,在使用该方法时,分层薄介质结构的垂直方向上,网格剖分的必须足够小,因而导致计算量的增大。而在使用矩量法分析时,常用的方法有谱域导抗法(SDI)和空域矩量法,其中使用谱域导抗法可以推导出分层介质中任意形状的金属贴片的谱域格林函数,基于混合双位方程(MPIE)的空域矩量法可以推导出空域格林函数。在实际处理过程中,会涉及到索莫菲尔德积分(SI),这个积分具有高振荡慢衰减的特性,可以采用使用离散复镜像法(DCIM)处理。本文是应用基于表面积分方程的矩量法来分析微带结构。首先从矩量法的基本原理入手,逐步分析了理想导体、纯介质及涂敷介质结构的模型,基于表面积分方程法,使用空间格林函数,得出不同类型散射体的表面积分方程,对公式进行了详细的推导,从而计算任意形状的大型散射体的远场分布。以此为基础,分析微带结构模型,同样利用表面积分方程法,得出微带结构的散射特性,改变馈电方式,从而算得微带天线等微带结构的辐射场。考虑到矩量法中不存在理想吸收边界,所以无反射的波端口的建模对天线馈电的计算至关重要。这里使用孔径耦合的等效原理和模式匹配法(MMM)对波端口进行建模,假设波端口外侧接一无限长同轴线,来模拟端口的匹配状态,进而求出微带结构天线、滤波器的辐射特性和S参数等。最后,本文简略地介绍了另外两种方法,即开路法和模拟匹配负载法,用以解决微带结构的阻抗匹配问题。与空域矩量法相比,本文方法操作更简便,不需要特意推导空域格林函数的解,也不需要处理索莫菲尔德积分,而且达到较高的精度。
[Abstract]:With the rapid development of communication industry, the requirement of miniaturization, light quality, high efficiency and so on has been put forward. The microstrip structure has been widely used because of its unique characteristics, and has been widely used in the fields of aviation, aerospace communication, etc. Therefore, the study of microstrip structure has become more and more important, and the analysis of electromagnetic scattering and radiation characteristics of microstrip structure has become a research field that can not be ignored. In the study of microstrip structure, the commonly used methods are FDTD (finite-difference time-domain method) and MOM (moment method). The finite difference time domain (FDTD) method is simple and versatile, and can be used to calculate the response of the whole frequency band at one time. However, in order to achieve the accuracy requirement, the vertical direction of the layered thin dielectric structure is obtained when using this method. The mesh must be small enough to increase the amount of computation. The spectral domain conductance method (SDI) and the spatial domain moment method (SDI) are commonly used in the analysis with the method of moment, in which the spectral domain Green's function of the metal patch of arbitrary shape in layered medium can be derived by using the spectral domain method. The spatial Green's function can be derived by the spatial moment method based on the mixed double position equation (MPIEs). In the process of practical processing, the Somerfeld integral (SI) is involved, which has the characteristics of high oscillation and slow attenuation, and can be processed by using discrete complex image method (DCIMM). In this paper, the method of moment based on surface integral equation is used to analyze the structure of microstrip. Starting with the basic principle of the method of moments, the models of ideal conductor, pure medium and coated medium are analyzed step by step. Based on the surface integral equation method and using the spatial Green's function, the surface area fractional equations of different types of scatterers are obtained. The formula is derived in detail to calculate the far-field distribution of large scatterers with arbitrary shape. On this basis, the microstrip structure model is analyzed, and the scattering characteristics of the microstrip structure are obtained by using the surface integral equation method, and the feeding mode is changed, thus the radiation field of the microstrip structure such as the microstrip antenna is calculated. Considering that there is no ideal absorbing boundary in the method of moments, the modeling of non-reflective wave ports is very important to the calculation of antenna feed. In this paper, the equivalent principle of aperture coupling and the mode matching method are used to model the wave port. Assuming an infinite coaxial line is attached to the outside of the wave port, the matching state of the port is simulated, and the microstrip structure antenna is obtained. The radiation characteristics and S parameters of the filter. Finally, two other methods, open circuit method and simulated matching load method, are briefly introduced to solve the impedance matching problem of microstrip structure. Compared with the spatial method of moments, this method is simpler to operate, and does not need to deduce the solution of the spatial Green's function, nor does it need to deal with the Sommerfeld integral, and achieves a higher accuracy.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN822

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