Coating As Well As The Electromagnetic Scattering Of Thin Dielectric Calculate The Quick Way

Along with the development of modern techniques dramatically,there is a wide variety application of thin dielectric sheet and conducting bodies with dielectric coating of uniformity for protection or aerodynamic reasons.More and more nonmetallic structures have replaced metallic for the expanding applications requirement to reduce weight or radar cross section, especially in the construction of modern aircraft and applications in aspect of ocean military such as in the domains of the radar target stealth.Background of the rush,there has been a growing interest in the research of the dielectric sheet and conducting bodies with uniformity dielectric coating,and notable approaches of sorts spurt out for treating such problem. Besides, take advantage of the expanding capabilities of digital computers,the numerical techniques of electromagnetical developments dramatically which contained the approaches for treating integral equation,just as the notable and moments method which gradually to perfect.In this paper,a numerical solution using the method of moments for high efficient calculation of electromagnetic scattering from thin dielectric sheet and dielectric coating of uniformity is studied.In the frist section,the historical background of the electromagnetic research and the subject studied in this dissertation is summarized.In Chapter Two, the foundation of my subjects:MoM, FMM and MLFMM are generally introduced,then the advantages and disadvantages of them are discussed.Aiming at the analyzing the electromagnetic scattering character of conducting bodies with dielectric coating of uniformity, In Chapter Three, the RCS of the coated objects is computing by use of the approximate impedance boundary condition (IBC).IBC introduces a relationship between the electric current and the magnetic current on the surface of coated dielectric.As the IBC based on the electric field integral equation proved excellent accuracy but ill-conditioned moments matrics,meanwhile, the IBC based on the magnetic field integral equation can obtain a well-condition moments matrics but the accuracy has been questioned, furthermore it applies only to closed surfaces. Consequently,in this paper,we examined the well-posedness of the combined field integral equation extended for scatterers satisfying the IBC,which maintain the efficiency and accuracy and moreover, is avoid resonance. The multilevel fast multipole method (MLFMA) is introduced into these integral equation to improve the efficiency.And so it can solve the problems which are large in terms of the wavelength. In Chapter Four,in the first,the conventional thin dielectric sheet surface integral equation is reviewed.The approach is favored because the volume integral equation(VIE) degenerates into a surface integral equation,which is easier to solve.And due to its simplicity and inadequency for certain problems,a new surface integral equation is proposed to fill the gap.This new formulation takes both tangential and normal pulse currents into account so that it can compute the RCS of the coated objects efficiency.In Chapter Five, A proposed surface electric field integral equation for thin dielectric sheets is combined with that for conductors to handle objects consisting of both dielectric and conducting materials.Lastly, the study in this paper is summarized, and forecasted of the subject.