Target Electromagnetic Scattering Characteristics Of Thin Dielectric Coating Analysis

With the quick development of technology for military and civil, thin materials are urgently used in aircraft and ship design and as coating in radar absorbing material used to reduce the radar cross section of an object. On the other hand, for microwave planar structure and patch antennas, they are also composed of conductor and thin materials. So the accurate and efficient modeling of thin materials and coatings has become more and more important.The Method of Moment is used in the integral equation. The thesis analyzes electromagnetic scattering of conductor-backed thin materials for closed bodies. An integral equation is obtained using the equivalence principle to replace the scattering object with an equivalent source and then applying the appropriate boundary condition at the surface of scatterer. The polarization current and charges are expressed in term of the surface induced current on the conductor so that only one unknown results. So it will decrease more unknowns that compares with PEC-TDS, surface integral equation, surface-volume integral equation, and so on. And it can also decrease computer resource and expedite the simulation process.Specially, when the thin materials coatings are added without increasing extra unknowns, only need the surface induced current on the conductor, which can decrease more and more unknowns with the increasing of the thin materials layers. The numerical results are presented in the thesis, showing the accuracy and validity of these solutions.The thesis also analyzes electromagnetic scattering of conductor-backed thin materials for open bodies. Because of duplicating the "top" surface mesh with an identical mesh to represent the bottom, one times unknowns are added compared with conductor-backed thin materials for closed bodies. But when the thin materials coatings are added without increasing extra unknowns, it can also decrease more unknowns. The numerical results are presented in the thesis, showing the accuracy and validity of these solutions.Method of Moment has been widely used in the analysis of the electromagnetic scattering problems, but it consumes more memory and CPU time while the object's electrical size increases. Multilevel Fast Multipole Approach can remarkably decrease numerical memory requirement and computation time, and is used to analyze electro-magnetic scattering of complex objects with electrically large size. Finally, the Multilevel Fast Multipole Approach is paralleled to makes it possible to analyze electromagnetic scattering for arbitrarily-shaped electrically-larger complex objects.In addition, this method only needs to discretize the conductor using planar triangles. If a thin material is present, then a thickness and permittivity are read for the material parameters of the element in the program. It is convenient to engineering application.