To solve the electromagnetic scattering problem for homogeneous dielectric bodies of revolution(BOR),a fast inhomogeneous plane wave algorithm is developed.By using the Weyl identity and designing a proper integration...To solve the electromagnetic scattering problem for homogeneous dielectric bodies of revolution(BOR),a fast inhomogeneous plane wave algorithm is developed.By using the Weyl identity and designing a proper integration path,the aggregation and disaggregation factors can be derived analytically.Compared with the traditional method of moments(MoM),both the memory and CPU time requirements are reduced for large-scale homogeneous dielectric BOR problems.Numerical results are given to demonstrate the validity and the efficiency of the proposed method.展开更多
Electromagnetic scattering from targets situated in half space is solved by applying fast inhomogeneous plane wave algorithm combined with a tabulation and interpolation method.The integral equation is set up based on...Electromagnetic scattering from targets situated in half space is solved by applying fast inhomogeneous plane wave algorithm combined with a tabulation and interpolation method.The integral equation is set up based on derivation of dyadic Green's functions in this environment.The coupling is divided into nearby region and well-separated region by grouping.The Green's function can be divided into two parts:primary term and reflected term.In the well-separated region,the two terms are both expressed as Sommerfeld integral,which can be accelerated by deforming integral path and taking interpolation and extrapolation.For the nearby region,the direct Sommerfeld integral makes the filling of impedance matrix time-expensive.A tabulation and interpolation method is applied to speed up this process.This infinite integral is pre-computed in sampling region,and a two-dimensional table is then set up.The impedance elements can then be obtained by interpolation.Numerical results demonstrate the accuracy and efficiency of this algorithm.展开更多
对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole...对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole Algorithm,MLFMA)计算曲线进行对比,验证了程序的正确性,说明其可用于飞行器表面不连续特征研究。采用数值方法详细研究了单缝隙、三缝隙电磁散射与入射电磁波频率的变化关系。数值计算结果表明,入射电磁波频率增加时,对单缝隙,电磁散射增强,雷达散射截面算术均值增加,其中掠入射角域内的均值增加最为明显;同时单缝隙的散射曲线相似、次波峰向外偏移;对三缝隙,除具有单缝隙的特性外,还表现为相互耦合性、曲线振荡增强,通过分析认为3个单缝隙散射不同相位的相互叠加导致了其散射的耦合性,入射频率增加时,散射叠加的峰值位置发生相应变化,表现为耦合作用和振荡作用更加明显。该结论可以用来进行飞行器表面的缝隙散射的减缩设计,从而有效提高飞行器的隐身性能。展开更多
基金supported in part by the National Science Foundation of China(No.60971032)in part by the Programme of Introducing Talents of Discipline to Universities under Grant b07046in part by the Joint Ph.D.Fellowship Program of the China Scholarship Council.
文摘To solve the electromagnetic scattering problem for homogeneous dielectric bodies of revolution(BOR),a fast inhomogeneous plane wave algorithm is developed.By using the Weyl identity and designing a proper integration path,the aggregation and disaggregation factors can be derived analytically.Compared with the traditional method of moments(MoM),both the memory and CPU time requirements are reduced for large-scale homogeneous dielectric BOR problems.Numerical results are given to demonstrate the validity and the efficiency of the proposed method.
文摘Electromagnetic scattering from targets situated in half space is solved by applying fast inhomogeneous plane wave algorithm combined with a tabulation and interpolation method.The integral equation is set up based on derivation of dyadic Green's functions in this environment.The coupling is divided into nearby region and well-separated region by grouping.The Green's function can be divided into two parts:primary term and reflected term.In the well-separated region,the two terms are both expressed as Sommerfeld integral,which can be accelerated by deforming integral path and taking interpolation and extrapolation.For the nearby region,the direct Sommerfeld integral makes the filling of impedance matrix time-expensive.A tabulation and interpolation method is applied to speed up this process.This infinite integral is pre-computed in sampling region,and a two-dimensional table is then set up.The impedance elements can then be obtained by interpolation.Numerical results demonstrate the accuracy and efficiency of this algorithm.
文摘对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole Algorithm,MLFMA)计算曲线进行对比,验证了程序的正确性,说明其可用于飞行器表面不连续特征研究。采用数值方法详细研究了单缝隙、三缝隙电磁散射与入射电磁波频率的变化关系。数值计算结果表明,入射电磁波频率增加时,对单缝隙,电磁散射增强,雷达散射截面算术均值增加,其中掠入射角域内的均值增加最为明显;同时单缝隙的散射曲线相似、次波峰向外偏移;对三缝隙,除具有单缝隙的特性外,还表现为相互耦合性、曲线振荡增强,通过分析认为3个单缝隙散射不同相位的相互叠加导致了其散射的耦合性,入射频率增加时,散射叠加的峰值位置发生相应变化,表现为耦合作用和振荡作用更加明显。该结论可以用来进行飞行器表面的缝隙散射的减缩设计,从而有效提高飞行器的隐身性能。
