When calculating electromagnetic scattering using method of moments （MoM）, integral of the singular term has a significant influence on the results. This paper transforms the singular surface integral to the contour...When calculating electromagnetic scattering using method of moments （MoM）, integral of the singular term has a significant influence on the results. This paper transforms the singular surface integral to the contour integral. The integrand is expanded to Taylor series and the integral results in a closed form. The cut-off error is analyzed to show that the series converges fast and only about 2 terms can agree wel with the accurate result. The comparison of the perfect electric conductive （PEC） sphere＇s bi-static radar cross section （RCS） using MoM and the accurate method validates the feasibility in manipulating the singularity. The error due to the facet size and the cut-off terms of the series are analyzed in examples.展开更多
An efficient hybrid method based on the method of moments （MOM） and physical optics （PO） for the analysis of radiation characteristics of an electrically large antenna-radome system is presented. Specifically, MOM...An efficient hybrid method based on the method of moments （MOM） and physical optics （PO） for the analysis of radiation characteristics of an electrically large antenna-radome system is presented. Specifically, MOM is first applied to the antenna to find the current on its surface, and then the equivalent PO currents produced by the antenna radiation are assumed on the radome wall. When the coupling of the PO currents and antenna current is considered, the coupling matrix is divided into a series of partial matrices, in order to deduce the memory requirement and accelerate the evaluation process. Numerical results indicate that the proposed hybrid PO-MOM method is accurate and efficient.展开更多
针对包含精细结构的电大尺寸目标电磁散射快速计算问题,提出了一种计算包含精细结构的电大尺寸目标电磁散射问题的基于矩阵降维的混合算法。该方法在Rao-Wilton-Glisson基函数矩量法(method of moment,MoM)的基础上,对目标区域进行划分...针对包含精细结构的电大尺寸目标电磁散射快速计算问题,提出了一种计算包含精细结构的电大尺寸目标电磁散射问题的基于矩阵降维的混合算法。该方法在Rao-Wilton-Glisson基函数矩量法(method of moment,MoM)的基础上,对目标区域进行划分,完成阻抗矩阵的分块和未知量的分离,再由矩量区与物理光学(physical optics,PO)区之间的电流相互作用构造耦合转移矩阵和激励转移矩阵,从而建立两个区域未知量之间的线性关系,进而完成对阻抗矩阵的降维,最终从矩阵运算角度构建了一种MoM-PO混合算法。其中,使用等效电偶极子模型简化双重积分计算,进一步减少矩阵元素的计算量;阻抗矩阵的阶数大幅减少,避免了大规模矩阵方程的求解计算。算例结果表明,与传统的低频算法相比,该算法既保证了计算精度,又提高了计算效率。展开更多
The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering ...The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering problems. As the number of unknowns increases, the size of Method Of Moments (MOM) impedance matrix grows very rapidly, so it is a prohibitive task for the computation of wideband Radar Cross Section (RCS) from electrically large object or multi-objects using the traditional AWE technique that needs to solve directly matrix inversion. In this paper, an AWE technique based on the Characteristic Basis Function (CBF) method, which can reduce the matrix size to a manageable size for direct matrix inversion, is proposed to analyze electromagnetic scattering from multi-objects over a given frequency band. Numerical examples are presented to il-lustrate the computational accuracy and efficiency of the proposed method.展开更多
As a marked extension of the traditional MoM-PO （method of moment-physical optics） hybrid method, a new hybridization of PO, SBR, and MoM （MoM-SBR/PO） is presented to calculate the multireflection contribution in ...As a marked extension of the traditional MoM-PO （method of moment-physical optics） hybrid method, a new hybridization of PO, SBR, and MoM （MoM-SBR/PO） is presented to calculate the multireflection contribution in the PO region efficiently by introducing the method of SBR based on RDN notion, which avoids the time-consuming iterative procedure and the choice of proper Green＇s function. As compared with the traditional MoM-PO hybrid method, the calculation efficiency of the proposed method is greatly improved, and its validity is verified by numerical results.展开更多
The Volume-Surface Current Continuity Method (VSCCM) is presented to analyze electromagnetic radiation from microstrip antenna. The microstrip antenna is discretized into small triangular patches on conducting surface...The Volume-Surface Current Continuity Method (VSCCM) is presented to analyze electromagnetic radiation from microstrip antenna. The microstrip antenna is discretized into small triangular patches on conducting surface and tetrahedral volume cells in dielectric region. The Method of Moments (MoM) is applied to solve the integral equation. An equation contains the restriction relation between the volume and surface current coefficient is derived from the current continuity equation at those parts where the conducting surface is in contact with the dielectric material. A simple equivalent strip model is introduced in the treatment of the feeding probe in VSCCM. The VSCCM can reduce the unknowns required to be solved in MoM, as well as the condition number of the matrix equation. Numerical results are given to validate the accuracy and efficiency of this method.展开更多
基金supported by the National Natural Science Foundationof China for the Youth(51307004)
文摘When calculating electromagnetic scattering using method of moments （MoM）, integral of the singular term has a significant influence on the results. This paper transforms the singular surface integral to the contour integral. The integrand is expanded to Taylor series and the integral results in a closed form. The cut-off error is analyzed to show that the series converges fast and only about 2 terms can agree wel with the accurate result. The comparison of the perfect electric conductive （PEC） sphere＇s bi-static radar cross section （RCS） using MoM and the accurate method validates the feasibility in manipulating the singularity. The error due to the facet size and the cut-off terms of the series are analyzed in examples.
基金the National Natural Science Foundation of China (60471040)
文摘An efficient hybrid method based on the method of moments （MOM） and physical optics （PO） for the analysis of radiation characteristics of an electrically large antenna-radome system is presented. Specifically, MOM is first applied to the antenna to find the current on its surface, and then the equivalent PO currents produced by the antenna radiation are assumed on the radome wall. When the coupling of the PO currents and antenna current is considered, the coupling matrix is divided into a series of partial matrices, in order to deduce the memory requirement and accelerate the evaluation process. Numerical results indicate that the proposed hybrid PO-MOM method is accurate and efficient.
文摘针对包含精细结构的电大尺寸目标电磁散射快速计算问题,提出了一种计算包含精细结构的电大尺寸目标电磁散射问题的基于矩阵降维的混合算法。该方法在Rao-Wilton-Glisson基函数矩量法(method of moment,MoM)的基础上,对目标区域进行划分,完成阻抗矩阵的分块和未知量的分离,再由矩量区与物理光学(physical optics,PO)区之间的电流相互作用构造耦合转移矩阵和激励转移矩阵,从而建立两个区域未知量之间的线性关系,进而完成对阻抗矩阵的降维,最终从矩阵运算角度构建了一种MoM-PO混合算法。其中,使用等效电偶极子模型简化双重积分计算,进一步减少矩阵元素的计算量;阻抗矩阵的阶数大幅减少,避免了大规模矩阵方程的求解计算。算例结果表明,与传统的低频算法相比,该算法既保证了计算精度,又提高了计算效率。
基金Supported by the National Natural Science Foundation of China (No. 60771034 )the 211 Project of Anhui University
文摘The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering problems. As the number of unknowns increases, the size of Method Of Moments (MOM) impedance matrix grows very rapidly, so it is a prohibitive task for the computation of wideband Radar Cross Section (RCS) from electrically large object or multi-objects using the traditional AWE technique that needs to solve directly matrix inversion. In this paper, an AWE technique based on the Characteristic Basis Function (CBF) method, which can reduce the matrix size to a manageable size for direct matrix inversion, is proposed to analyze electromagnetic scattering from multi-objects over a given frequency band. Numerical examples are presented to il-lustrate the computational accuracy and efficiency of the proposed method.
文摘As a marked extension of the traditional MoM-PO （method of moment-physical optics） hybrid method, a new hybridization of PO, SBR, and MoM （MoM-SBR/PO） is presented to calculate the multireflection contribution in the PO region efficiently by introducing the method of SBR based on RDN notion, which avoids the time-consuming iterative procedure and the choice of proper Green＇s function. As compared with the traditional MoM-PO hybrid method, the calculation efficiency of the proposed method is greatly improved, and its validity is verified by numerical results.
基金Supported by Natural Science Foundation of Fujian Province of China (2011J01348)the Science and Technique Major Program of Fujian Province (2010HZ-0004-1)
文摘The Volume-Surface Current Continuity Method (VSCCM) is presented to analyze electromagnetic radiation from microstrip antenna. The microstrip antenna is discretized into small triangular patches on conducting surface and tetrahedral volume cells in dielectric region. The Method of Moments (MoM) is applied to solve the integral equation. An equation contains the restriction relation between the volume and surface current coefficient is derived from the current continuity equation at those parts where the conducting surface is in contact with the dielectric material. A simple equivalent strip model is introduced in the treatment of the feeding probe in VSCCM. The VSCCM can reduce the unknowns required to be solved in MoM, as well as the condition number of the matrix equation. Numerical results are given to validate the accuracy and efficiency of this method.
