| Non-metallic materials and composites are now commonplace in modern vehicle construction and crucial to the operation of many microwave devices. Material properties of the body affect the electromagnetic scattering greatly. Impedance boundary conditions have proved effective for simplifying calculations dealing with material surface whose solution wound be difficult or impractical without then.In this thesis, scattering of coating constructions and impedance boundary conditions were considered. The comprehensive treatment of a variety of approximate boundary conditions, such as: standard boundary condition (SIBC), generalized boundary condition and exact boundary condition, applied to electromagnetic. Methods for deriving them and relationships and differences of these boundary conditions are discussed. Next, impedance boundary conditions are used to simulate the properties of material which coating outer of the perfect electric conductor. Formulations of the method of moment (MoM) and iterative physical optics (IPO) are given in detail and how to improve the calculating accuracy and efficiency are discussed. Finally, some calculated results are given in order to demonstrate the validation of the theory presented formerly. |
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