An iterative physical optics（IPO） model is proposed to solve extra large scale electric electromagnetic（EM） scattering from randomly rough surfaces. In order to accelerate the convergence of the IPO model, the for...An iterative physical optics（IPO） model is proposed to solve extra large scale electric electromagnetic（EM） scattering from randomly rough surfaces. In order to accelerate the convergence of the IPO model, the forward-backward methodology and its modification with underrelaxation iteration are developed to simulate the rough surface scattering; the local iteration methodology and the fast far field approximation（Fa FFA） in the matrix-vector product are proposed to reduce greatly the computational complexity. These techniques make Monte Carlo simulations possible. Thus, the average Doppler spectra of backscattered signals obtained from the simulations are compared for different incident angles and sea states. In particular, the simulations show a broadening of the Doppler spectra for a more complicated sea state at a low grazing angle（LGA）.展开更多
The physical optics solution is presented for the calculation of scattering by the complex conducting bodies coated with anisotropic materials, which is based on the tangential plane approximation and the equivalent c...The physical optics solution is presented for the calculation of scattering by the complex conducting bodies coated with anisotropic materials, which is based on the tangential plane approximation and the equivalent currents on an anisotropic material backed by an infinite metal surface illuminated by the plane wave given in our previous work. The analytical scheme is proposed to realize fast computation of the solution. Numerical results for several coated bodies such as dihedral corner reflector and cone-cylinder geometry are given and discussed.展开更多
Based on a first-order state-vector differential equation representation of Maxwell's equations, an analytical formulation is derived for the equivalent currents on an anisotropic material backed by a metal surfa...Based on a first-order state-vector differential equation representation of Maxwell's equations, an analytical formulation is derived for the equivalent currents on an anisotropic material backed by a metal surface, and the relation between two currents is also considered. These expressions are degenerated into the common forms for some simple cases. This effort will provide the theoretical preparation for the approximate calculation of electromagnetic scattering from a conducting object coated by an anisotropic material.展开更多
对频域等效边缘流(Equivalent edge current EEC)公式进行傅里叶逆变换,推导出时域等效边缘流(TD-EEC)的计算公式,可用于计算任意导体直劈边缘在任意观察方向的远区时域绕射场,且绕射线在焦散区内保持有限。TD-EEC的时域边缘绕射的计入...对频域等效边缘流(Equivalent edge current EEC)公式进行傅里叶逆变换,推导出时域等效边缘流(TD-EEC)的计算公式,可用于计算任意导体直劈边缘在任意观察方向的远区时域绕射场,且绕射线在焦散区内保持有限。TD-EEC的时域边缘绕射的计入明显改善了TD-PO方法的计算结果,能够用于电大尺寸复杂导体目标的瞬态散射和宽带散射分析以及雷达原始回波的模拟。最后,以平板和劈柱为例进行瞬态电磁散射计算,并将计算结果同TD-PO和时域有限差分(FDTD)的计算结果进行比较,验证了方法的正确性和有效性。展开更多
基金supported by the National Natural Science Foundation of China(61372033)
文摘An iterative physical optics（IPO） model is proposed to solve extra large scale electric electromagnetic（EM） scattering from randomly rough surfaces. In order to accelerate the convergence of the IPO model, the forward-backward methodology and its modification with underrelaxation iteration are developed to simulate the rough surface scattering; the local iteration methodology and the fast far field approximation（Fa FFA） in the matrix-vector product are proposed to reduce greatly the computational complexity. These techniques make Monte Carlo simulations possible. Thus, the average Doppler spectra of backscattered signals obtained from the simulations are compared for different incident angles and sea states. In particular, the simulations show a broadening of the Doppler spectra for a more complicated sea state at a low grazing angle（LGA）.
文摘The physical optics solution is presented for the calculation of scattering by the complex conducting bodies coated with anisotropic materials, which is based on the tangential plane approximation and the equivalent currents on an anisotropic material backed by an infinite metal surface illuminated by the plane wave given in our previous work. The analytical scheme is proposed to realize fast computation of the solution. Numerical results for several coated bodies such as dihedral corner reflector and cone-cylinder geometry are given and discussed.
文摘Based on a first-order state-vector differential equation representation of Maxwell's equations, an analytical formulation is derived for the equivalent currents on an anisotropic material backed by a metal surface, and the relation between two currents is also considered. These expressions are degenerated into the common forms for some simple cases. This effort will provide the theoretical preparation for the approximate calculation of electromagnetic scattering from a conducting object coated by an anisotropic material.
文摘对频域等效边缘流(Equivalent edge current EEC)公式进行傅里叶逆变换,推导出时域等效边缘流(TD-EEC)的计算公式,可用于计算任意导体直劈边缘在任意观察方向的远区时域绕射场,且绕射线在焦散区内保持有限。TD-EEC的时域边缘绕射的计入明显改善了TD-PO方法的计算结果,能够用于电大尺寸复杂导体目标的瞬态散射和宽带散射分析以及雷达原始回波的模拟。最后,以平板和劈柱为例进行瞬态电磁散射计算,并将计算结果同TD-PO和时域有限差分(FDTD)的计算结果进行比较,验证了方法的正确性和有效性。
