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1.
魏兴昌  梁昌洪 《电子学报》2001,29(12):1668-1670
本文利用Coifman尺度函数具有消失矩和紧支集的特点,提出了一种新的多分辨时域分析方法,研究了它的数值色散特性,并与通常的FDTD方法进行了比较.通过算例,表明该方法比通常的FDTD方法需要网格数量少、计算时间快.  相似文献   

2.
应用FDTD结合MP的方法计算了波导加载谐振器的谐振频率和品质因数。与FDTD/DFT方法比较,这种方法减少了对FDTD运行时间的需求,并且提高了数值精度。与FDTD/Prony方法比较,其优点是计算效率高,对噪声的敏感小。文中以计算实例说明了算法的有效性。  相似文献   

3.
王加莹  高本庆 《电子学报》1999,27(2):142-144
本文用FDTD法处理复合型导体结构中电磁场的耦合和传输时,用一种子域连接法建立数学模型,以分析波导元件散射特性和波导口径面天线的辐射特性为例来这种方法的具体运用。这种方法具有节省计算空间和计算时间,建模灵活多样等优点。  相似文献   

4.
TF/SF(Total Field/Scattered Field)法是FDTD(Finite-Difference Time—Domain)数值算法中引入平面波源的有效方法之一。本文对TF/SF法中的一维辅助渡源法进行改进,首先推导出三维FDTD网格内的电磁波传播群速和相速的近似解析解。为预测离散网格内电磁波传播提供理论基础;然后以此为依据,提出对一维辅助波源的时域群速补偿法。经过实际三维FDTD问题的数值模拟,证实了本文方法在保持一维辅助波源法高效简洁的同时,进一步减少了泄露误差,给FDTD计算散射问题提供了有力工具。  相似文献   

5.
A hybrid time-domain numerical method based on finite-difference technique and moment method is proposed. Starting from Maxwell's differential equations, our method uses Yee's finite difference scheme in the space domain, but does not utilize the customary explicit leap-frog time scheme. Instead, in the time domain, the fields are expanded in a series of basis functions and treated by a moment method procedure. By choosing appropriate basis functions and testing functions, the conventional finite-difference time-domain (FDTD) formulation and the order-marching unconditionally stable FDTD scheme can be derived from our method as two special cases. Finally, we use triangle basis functions and Galerkin's testing procedure to get an implicit formulation. To verify the accuracy and efficiency of the new formulation, we compare the results with the FDTD method. Our method improves computational efficiency notably, especially for multiscale problems with fine geometric structures, which is restricted by stability constrain in the FDTD method.  相似文献   

6.
FDTD analysis of phased array antennas   总被引:1,自引:0,他引:1  
This work presents a new application of the finite-difference time-domain (FDTD) method to the generalized analysis of phased array antennas. The generality of the FDTD method brings important advantages to the phased array antenna analysis problem, allowing the modeling of complex conductor and dielectric geometries with relative ease. Additionally, a new broad-band FDTD periodic boundary condition is developed which allows the array problem to be simplified to a periodic unit cell computational domain. This hybrid frequency/time-domain periodic boundary condition enables solution of the periodic phased array problem for arbitrary scan conditions in a broadband fashion. The new method is applied to waveguide and stacked microstrip antenna arrays and the numerical results are compared to experimental or analytic solutions, demonstrating the validity and utility of this method  相似文献   

7.
A new way to carry out numerical cellular telephone simulation in the presence of the head is presented. Here, two finite-difference time-domain (FDTD) simulations with different spatial and time resolutions are sequentially combined to perform a dual-grid FDTD (DG-FDTD) simulation. The DG-FDTD approach has the significant advantages to remain stable along the computation and to be easy to implement in a typical FDTD code. When compared with classical FDTD analysis, the DG-FDTD approach exhibits a reduction in computation time and memory requirements by a factor of 2.3 and 3.2, respectively, while providing accurate results both in near-field and far-field radiation.  相似文献   

8.
将多区域时域伪谱(MPSTD)与时域有限差分(FDTD)相结合的混合算法应用于同轴馈电耦合微带天线的分析,该混合算法充分发挥两种时域算法的优越性,对同轴馈电耦合微带天线进行了准确建模与快速分析,数值仿真验证了该算法的有效性和准确性。  相似文献   

9.
不规则贴片微带天线的MPSTD-FDTD混合算法分析   总被引:2,自引:0,他引:2       下载免费PDF全文
 针对不规则贴片微带天线的准确建模与快速分析,将多区域时域伪谱(MPSTD)与时域有限差分(FDTD)两种时域算法相结合,提出了MPSTD-FDTD混合算法,以此来充分发挥两种时域算法的优越性.文中首先给出了混合算法的具体实现方法,并简要推导了混合算法中子域分界面上的匹配条件.其次,分析了算法的计算精度和影响计算精度的主要因素.最后,利用该混合算法对一种倾斜矩形贴片微带天线进行了分析,数值仿真验证了算法的有效性和准确性.  相似文献   

10.
UPML媒质中无条件稳定的二维ADI-FDTD方法   总被引:2,自引:0,他引:2  
赵延文  聂在平 《电波科学学报》2002,17(6):586-589,603
对单轴各向异性PML(UPML)媒质中二维TM波的交变方向隐式时域有限差分方向(ADI-FDTD),通过计算实例表明,ADI-FDTD方法在UMPL媒质中是无条件稳定的,其时间步长不受CFL稳定性条件的限制,并且当计算区域内具有精细差分网格时,其计算效率明显优于传统的时域有限差分方向(FDTD)。  相似文献   

11.
The numerical dispersion property of the two-dimensional alternating-direction implicit finite-difference time-domain (2D ADI FDTD) method is studied. First, we notice that the original 2D ADI FDTD method can be divided into two sub-ADI FDTD methods: either the x-directional 2D ADI FDTD method or the y-directional 2D ADI FDTD method; and secondly, the numerical dispersion relations are derived for both the ADI FDTD methods. Finally, the numerical dispersion errors caused by the two ADI FDTD methods are investigated. Numerical results indicate that the numerical dispersion error of the ADI FDTD methods depends highly on the selected time step and the shape and mesh resolution of the unit cell. It is also found that, to ensure the numerical dispersion error within certain accuracy, the maximum time steps allowed to be used in the two ADI FDTD methods are different and they can be numerically determined  相似文献   

12.
用CAD技术实现复杂目标FDTD方法几何-电磁建模   总被引:7,自引:1,他引:6  
FDTD方法是近年来得到广泛研究和应用的数值方法,具有许多无可比拟的优越性。CAD技术的介入使FDTD方法向实用化方向迈出了一大步。本文介绍如何使用CAD软件,基于复杂目标的设计图、剖面线图等描述方式,生成提供给FDTD计算程序使用的目标的几何-电磁参量描述文件。本文借助该方法计算了一种飞机在谐振区的RCS。  相似文献   

13.
The theory of a singularity-enhanced FDTD method for diagonal metal edges   总被引:1,自引:0,他引:1  
The complete theory of a singularity-enhanced finite-difference time-domain (FDTD) method for a sharp diagonal metal edge is presented. This method is very accurate and efficient for modeling printed microwave components with diagonal metal edges including some microstrip patch antennas, various other printed antennas, and printed transmission lines. Considering the singular nature of electromagnetic fields at a sharp metal edge, new FDTD equations are derived for all electric and magnetic nodes near the edge, using a contour-path subcell approach. The new FDTD equations for the affected nodes differ from the standard (Yee's) FDTD equations only by a few additional coefficients, for which complete mathematical expressions are given. Application of this method to several antenna and transmission-line problems demonstrated significantly improved accuracy over previous methods, without any noticeable computing overhead. A coarse grid can be used in conjunction with this method and hence the required computer memory and time can be reduced drastically. We have used the maximum allowed time step in all our applications and the method was always stable.  相似文献   

14.
In this paper, a new finite-difference time-domain (FDTD) algorithm is investigated to analyze electromagnetic structures with curved boundaries using a Cartesian coordinate system. The new algorithm is based on a nonorthogonal FDTD method. However, only those cells near the curved boundaries are calculated by nonorthogonal FDTD formulas; most of the grid is orthogonal and can be determined by traditional FDTD formulas. Therefore, this new algorithm is more efficient than general nonorthogonal FDTD schemes in terms of computer resources such as memory and central processing unit (CPU) time. Simulation results are presented and compared to those using other methods  相似文献   

15.
An efficient time-domain method based on a compact two-dimensional (2-D) finite-difference time-domain (FDTD) method combined with weighted Laguerre polynomials has been proposed to analyze the propagation properties of uniform transmission lines. Starting from Maxwell's differential equations corresponding to the compact 2-D FDTD method, we use the orthonormality of weighted Laguerre polynomials and Galerkin's testing procedure to eliminate the time variable. Thus, an implicit relation, which results in a marching-on-in-degree scheme, can be obtained. To verify the accuracy and efficiency of the hybrid method, we compare the results with those from the conventional compact 2-D FDTD and compact 2-D alternating-direction-implicit (ADI) FDTD methods. The hybrid method improves the computational efficiency notably, especially for complex problems with fine structure details that are restricted by stability constrains in the FDTD method.  相似文献   

16.
The piecewise linear current density recursive convolution (PLCDRC) finite-difference time-domain (FDTD) method for isotropic dispersive media greatly improves accuracy over recursive convolution (RC) and current density recursive convolution (CDRC) FDTD approaches but retains its speed and efficiency advantages. This letter extends this approach to anisotropic magnetoactive plasmas which incorporates both anisotropy and frequency dispersion at the same time, enabling the transient solutions of electromagnetic wave propagation in anisotropic magnetoactive plasmas. The high efficiency and accuracy of the method are confirmed by computing the reflection and transmission through a magnetized plasma layer, with the direction of propagation parallel to the direction of the biasing field. A comparison to frequency-domain analytic results and CDRC FDTD results is included.  相似文献   

17.
Adapted finite-difference time-domain (FDTD) update equations exist for a number of objects that are smaller than the grid step, such as wires and thin slots. We provide a technique that automatically generates new FDTD update equations for small objects. Our presentation focusses on 2D-FDTD. We start from the FDTD equations in a fine grid where the time derivative is not discretised. This yields a large state-space model that is drastically reduced with a reduced order modeling technique. The reduced state-space model is then translated into new FDTD update equations that can be used in an FDTD simulation in the same way as the existing update equations for wires and thin slots. This technique is applied to a number of numerical problems showing the accuracy and versatility of the proposed method.  相似文献   

18.
The two-dimensional finite-difference time-domain (2-D FDTD) method is undeniably efficient for full-wave analysis of uniform transmission lines. However, conventional 2-D FDTD method ignores the spatial attenuation along the propagation direction and yields approximate results. We propose a new 2-D FDTD method for extracting exact attenuation constants of lossy transmission lines. In the proposed method, we take the variation of field components with the propagation direction into consideration and describe an iterative process for finding exact attenuation constants. Numerical experiments show that, compared with the conventional 2-D FDTD method, results given by the iterative process agree much better with analytical solutions or measured data.  相似文献   

19.
This paper introduces a novel parallel shift operator finite‐difference time‐domain (SO‐FDTD) method for plasma in the dispersive media. We calculate the interaction between the electromagnetic wave of various frequencies and non‐magnetized plasma by using the parallel SO‐FDTD method. Then, we compare the results, which are calculated with serial and parallel SO‐FDTD executions to obtain the speedup ratio and validate the parallel execution. We conclude that the parallel SO method has almost the same precision as the serial SO method, while the parallel approach expands the scope of memory and reduces the CPU time.  相似文献   

20.
A new FDTD algorithm based on alternating-direction implicit method   总被引:32,自引:0,他引:32  
In this paper, a new finite-difference time-domain (FDTD) algorithm is proposed in order to eliminate the Courant-Friedrich-Levy (CFL) condition restraint. The new algorithm is based on an alternating-direction implicit method. It is shown that the new algorithm is quite stable both analytically and numerically even when the CFL condition is not satisfied. Therefore, if the minimum cell size in the computational domain is required to be much smaller than the wavelength, this new algorithm is more efficient than conventional FDTD schemes in terms of computer resources such as central-processing-unit time. Numerical formulations are presented and simulation results are compared to those using the conventional FDTD method  相似文献   

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