有限周期电大尺寸频率选择面电磁散射特性的体面积分方法分析

【作者】 张辉；

【导师】 丁大志； 陈如山；

【作者基本信息】 南京理工大学 ， 电路与系统， 2009， 硕士

【摘要】 频率选择表面(FSS)的工程应用非常广泛,但到目前为止,对FSS的研究大部分仍假定其为平面的并且是无限大周期,而在实际应用中,FSS阵列通常是有限大结构,甚至是曲面的,而且加载介质。所以对有限尺寸加载介质FSS阵列的电磁分析具有重要的实用价值。在上述工程应用背景下,本文使用体面积分方程(VSIE)结合矩量法(MOM)来分析这种曲面有限周期加载介质FSS结构的传输特性。体面积分方程方法具有两个优点:一个是能够完全模拟任意形状FSS结构,另外就是比较容易应用多层快速多极子算法(MLFMA),来分析电大尺寸结构和加快求解速度。本文首先分析了VSIE的基本原理及其公式推导,利用VSIE方法分析了复杂介质金属混合结构的电磁散射,其中包括曲面有限周期加载介质FSS阵列结构的散射特性。接着本文介绍了有限尺寸FSS结构传输和反射特性的分析方法和给出了传输和反射系数的求解公式,并利用VSIE结合MLFMA方法分析了曲面有限周期FSS阵列加载介质时的传输和反射特性,其基本单元为方环和十字贴片,并分别对其平面波垂直入射和斜入射情况下的透射曲线和反射曲线进行分析,将计算结果与软件仿真的无限大周期单元的结果进行对比,可以看出结果显示了较好的选频特性。更多还原

【Abstract】 The engineering application of frequency selective surfaces (FSS) is broad. Up to now, most of the researches on the FSS still assumed that the FSS is planar and infinite-period array. But in practical applications, FSS arrays are usually finite structures, and sometimes are curved, even with dielectrics loaded. So the electromagnetic analysis on FSS with finite size and dielectric is valuable.In the background of mentioned Engineering applications, this article present a hybrid volume-surface integral-equation(VSIE) combined with moment method (MOM) to analyze the transmission and reflection characteristics of curved and finite FSS structures which have dielectric substrate. The hybrid integral equations approach has two advantages. One is the capability of modeling arbitrarily shaped FSS structures in detail, the other one allows us to easily apply the multilevel fast multipole algorithm (MLFMA) to analyze electrically large structures and speed up the solution speed.Firstly, this article also analysis the basic principles of VSIE and gives its formula. We use the method of VSIE to analysis the scattering of complex structure mixed with dielectrics and metal, including the curved and finite FSS structures, which FSS has dielectric substrate. This article also describes how to analysis the transmission and reflection characteristics of finite FSS, and gives the formula of transmission and reflection coefficient. The method of VSIE combined with MLFMA is used to analysis the curved and finite FSS structures loaded with dielectric substrate, these FSS are the arrays of Square-loop and Cross, then the transmission characteristics can be got from them. In the analysis, the normal incidence and oblique incidence of plane-wave are also considered in it. Then we analysis the transmission and reflection coefficient and compare them with some results got from simulating infinite-period array in a software, it can be seen that the results show a good characteristics of frequency-selective.更多还原