| Advanced composite materials are attractive as substitute for metals in avionic and military applications as aircraft and missiles due mainly to their superior mechanical properties. They are also used in targets with beyond-horizon radar detection areas. Among of them, graphite/epoxy and boron/epoxy fiber-reinforced laminated composites are widely used, however, they are anisotropic and marginal in conductivity. On the other hand, the radar absorbing materials (RAM) coated on the surface of metal object can reduce the radar cross section (RCS). Even some of them are anisotropy. Therefore, we need to research the characteristics of electromagnetic wave scattering from these coating targets and the technology of going into hiding so that we can make use of this technology to special areas.The finite-difference time-domain (FDTD) technique is one of the most commonly used numerical methods for the transient analysis of the electromagnetic (EM) field interaction with complex structures. It is based on the direct solution of the difference form of Maxwell's equations by means of the Yee's leap-frog discretization scheme. The technique has the advantage of being very flexible, because it can be applied to the scattering from complicated objects in free space, a wide variety of EM transient problems, and is easy to implement in computer codes.In this dissertation, the EM wave scattering problems from complex object coated with anisotropic materials are studied by using the FDTD method and other analytical methods. The following problems are considered: the EM wave reflection and transmission in the infinite layered anisotropic media, both FDTD and general transmission matrix (GTM) methods are applied to analyze the half space and layered anisotropic materials. Cylinder objects scattering coated with anisotropic lossy substance and wide-band scattering from complicated objects in free space, both plane wave expanded and FDTD method are used to compute the RCS of the 2-dimession objects as aerofoil with partly coated anisotropic RAM. The RCS of 3-dimession complicated bi-anisotropic object computed by FDTD methods.Firstly, we reconstructed the difference Maxwell's equations contained anisotropic medium in form of one-order normal difference equations on the transverse components of the EM field. Eigenvalues and Eigenvectors are obtained when we resolve these equations The matrix consisted of these eigenvalues is called GTM which is different from thatapplied to layered isotropic materials. The matrix proposed is a diagonal one, and it is a unit one when EM wave travels across boundary between two substances. We use the GTM method to discuss the coefficient of reflection and transmission from the half space, the multilayer anisotropy, and that of reflection from coating on the metal plane. The FDTD method has .been used to validate the result computed by GTM method.Secondly, the cylindrical rod made from transverse anisotropic material is studied by plane wave expended method. 2-dimenssion RCS formula is given which is used to calculate both bi-static and back scatting. Transient EM scattering analysis of targets coated with a lossy anisotropy is introduced into the FDTD method. The sample geometric objects are analyzed using both methods. The results computed by two methods are good agreement with one and the other.Thirdly, Based on the Maxwell's equations with dyadic parameters, the formula with bi-anisotropic media and general relationship has been proposed. It is contained every medium case: isotropy, bi-isotropy, anisotropy, and bi-anisotropy, also lossy and lossless. The formula is discretized with Yee's algorithm. To overcome the coupling between components of electro and magnetic field, average method is used. Some of the components are not located Yee's grid. They are substituted by near space lattice locative. By using this approach, we study the scattering problem of real 3-dimenssional object as a model airplane and a coated target.Finally, we enhance the FDTD method for simulating transi...
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