| The characteristics of high-frequency composite electromagnetic backscattering from a target above one- or two-dimensional conductor sea surfaces are investigated. The total composite scattering field can be split into first order scattering field and second order coupling scattering field to be calculated with the diffraction of the target fringe taken into account. The Kirchhoff Approximation (KA) is used to calculate the backscattering radar cross section (RCS) of 1-D and 2-D sea surface, respectively. The scattering field of sea surface versus incident angle and azimuth angle is presented. The impact of frequency and wind speed on RCS of sea surface is discussed. The RCS of conducting plate, rhombus, cube, cylinder, cone-cylinder and trapezia are computed by the method of equivalent edge currents (MEC). And it is compared to the results simulated by commercial software CST and FEKO, which get good agreement with each other. The reciprocity theorem method and the MEC are employed together to calculate the coupling scattering field between a target and sea surface. The numerical results of the backscattering RCS with different incident angle for the conducting plate, cone-cylinder and trapezia above the sea surface are presented, respectively, with the results improved from unconsidered diffraction. The dependence of the composite backscattering RCS on the target size, the height, the wind speed of sea surface and the frequency of incident wave is analyzed, which is in good agreement with the results of experiment. The time domain scattering field of sea surface is calculated based on the TDIE and the surface current of ocean is presented in the paper. The influence of incident angle on backward far field is analyzed. The theory of TD-EEC is introduced and the process of calculating time domain field of target is given.
|
PDF Full Text Request