Research On Fast Algorithm In Electromagnetic Scattering Of Targets In The Background Of Half Space

The research on the scattering characteristics of targets in the background of half space has precious value in radar guidance and interception, target identification and extraction of characteristics. Half spaces are usually formed by different kinds of complex media(i.e. dispersive and lossy media). Accurate modeling is crucial when considering the contribution of half space to the scattering problems. In this thesis, a hybrid electromagnetic equivalent model of scattering problems in half space is proposed, within the framework of surface equivalence principle. Study of the model is carried out later in the thesis. The major work of the research are stated below.Derivation of the equivalence equations which is suitable for modeling of electromagnetic scattering of target in the half space background. Based on integral equation method, according to the equivalence principle, the contribution of half space is described by electromagnetic equivalent sources distributed on the half space surface. Equations are derived in the way of PMCHW. These equations are suitable for the different relative position of targets, i.e. targets on either side of the half space surface and targets embedded the half space surface. Problems along with the physics model such as treatment of truncated edge and description of far field are solved.Numerical examples are calculated and studied in the backgrounds of sea and soil. Firstly, the calculation of electrical parameters of the specific media of sea or soil is discussed. According to the equivalence principle and its numeric program, several practical examples are proposed. Analysis on effect of half space and the distribution of electric current are performed.At last the validity of substituting the half space surface by a PEC surface in the scattering problem is investigated. Skin depth and reflection coefficient are two standard to examining soil and sea. Numerical examples of half space scattering problems would have their surface substituted by PEC, and results of the two circumstance are compared. More detailed analysis are made in the end.