| Because of the complexity of the practice target structure and composite material, its structure is not a single geometry, material is not a single metal or nonmetal material, therefore, the study of electromagnetic scattering characteristics with different materials, different combination of the research has a pressing needs. The physical optics(PO) algorithm based on Maxwell's equations, is recognized in the field of high frequency Electromagnetic field calculation has good applicability, especially on electrically large targets scattering and radiation problems can give satisfactory results. And as a zero wavelength in the ray optics approximation, geometrical optics(GO) theory, with its unique processing advantage under the uniform medium plane wave of energy transmission and scattering mechanism, can carry on the ray tracing to the given structure.This thesis, in combination with PO and GO algorithm on the basis of their respective advantages, analyzed and realized the PO algorithm and geometrical optics and physical optics(GO-PO) algorithm, and the medium target under the algorithm of reflection coefficient. Focus on combining with the two calculation methods of electromagnetic, from the simple to the portfolio models and complex targets to the dielectric coating, to a large number of numerical examples of specific electromagnetic simulation, calculation and analysis. Detailed work includes:1. Analyzed and solved the standards bodies(disk, square plate) in different cases of radar scattering cross section(RCS), by the method of Mie series, the scattering field of the sphere and cylinder was analyzed. O n the basis of further realized on any targets RCS PO theoretical calculation, with different models as a reference, the numerical tested and verified the reliability and versatility of the algorithm.2. In the realization of the PO for a solver, on the basis of introducing the GO to increase the multiple reflection ray tracing thought of contribution to the total field, triangle surface subdivision, the target for each bin for one or more fields to solve, and to each field of the coherent superposition, finally achieved GO-PO theory calculation models of PLD at random. The structure of dihedral angles coupling fields with different sizes, different incident wave frequenc ies and different polarization modes were solved and analyzed in detail. Especially for the sea and the ship's rail structure, sinusoidal model was adopted to simulate the combination of rough surface, the ship's rail with flat simplified representation, sine surface instead of rough surface. Analyzed in composite structure angle, and the size of the rough surface of the ups and downs, the electromagnetic scattering characteristics, the influence of electromagnetic scattering characteristics analysis for Ship Sea coupling model provided the basis. On the basis of a combination of further(three sides angle, hull structure radar mast simple combination model) and complex targets such as the small plane were used to solve the coupling fields.3. The changes of material properties under different polarization modes(HH and VV) were compared combined with different med iums, to modify the PO and the reflection coefficient of GO-PO algorithm. PO and GO-PO solutions of the medium targets were implemented, the coated side board and cone of scattering field of the medium were solved. The coupling fields of the coated with different mediums, different coating position of dihedral angle structures were solved by dielectric GO-PO algorithm. In addition, portfolio objectives such as the sea and the ship's rail structure coating medium and deck and antenna array coated with different mediums and complex targets such as missile model coated medium was made a detailed calculation and analyzed combined with a large number of examples as theoretical basis, the target RCS impacts of dielectric materials(the lossy and lossless mediums) were analyzed. |
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