磁化铁氧体覆盖二维导体目标FDTD分析的移位算子方法

Shift Operator Method Applied for Two-dimensional Conducting Target Coated with Magnetized Ferrite in FDTD Analysis

采用移位算子方法把时域有限差分法推广应用于二维磁各向异性色散介质—磁化铁氧体中.证明了电磁波横向入射二维轴向磁化铁氧体目标情形下,电磁波可按目标的轴向分解为横电波(TE波)和横磁波(TM波),且TE波的散射特性与铁氧体介质无关,而TM波的散射特性与介质电磁参量密切相关,同时对其物理原因进行了分析.通过采用移位算子方法处理磁化铁氧体频域本构关系,得到该情形下目标电磁散射的移位算子时域有限差的迭代计算公式,同时解决了电磁波在各向异性和频率色散介质中传播的问题.计算了轴向磁化铁氧体涂敷VonKarman型导体柱的TM波双站雷达散射截面,分析了铁氧体参量对目标双站雷达散射截面的影响.结果表明:恰当地选择铁氧体参量能有效地减少目标的雷达散射截面,本文时谐因子取exp〔jωt〕.

The finite-difference time-domain（FDTD） method is extended to two-dimensional magnetic anisotropic dispersive media-magnetized ferrite by using Shift Operator（SO）.It is proved that when the incident plane wave vector is perpendicular to the axis of the two-dimensional axial magnetized ferrite cylinder,the electromagnetic wave can be decomposed into Transverse Electric（TE） and Transverse Magnetic（TM） waves.The electromagnetic scattering characters of TE wave have no relation with the target,but the electromagnetic scattering characters of TM wave have close relations with the electromagnetic parameters in magnetized ferrite.The physical reasons are analyzed.The FDTD with shift operator（SO-FDTD） formulations in this case are derived based on the constitutive relation for magnetized ferrite and shift operator,which leads to the electromagnetic wave propagation of both anisotropy and frequency dispersion media being solved at the same time.For the electromagnetic scattering of Von Karman shaped conducting cylinder coated with anisotropic magnetized ferrite,the effect of the ferrite parameters on the bistatic Radar Cross Section（RCS） is investigated and some numerical results are obtained.The results indicate that an appropriate ferrite coating may efficiently reduce the RCS of a metallic target,and expjωt denotes the convention of time dependence.