| The characteristics of high-frequency composite electromagnetic scattering field from sea surfaces and simple target are investigated. Time domain physical optics (TDPO) is used to calculate the scattering field of a simple large convex target, and the method of time domain equivalent edge currents (TDEEC) is used to modify the edge diffraction field. The physical concept of time-domain method is clear, the scattering echo waveform of the target or sea can be calculated directly, and the broadband Radar cross section (RCS) can be obtained by Fourier transform. The scattering field of conducting ball and plate are computed, and is compared to the results simulated by commercial software XFDTD and FEKO, which get good agreement with each other. The electromagnetic scattering field from sea is calculated based on PM spectrum. The size of sea surfaces and discrete requirements versus wind speed are presented. Then the time-domain backscattering of sea surfaces is calculated by use of fragment method. The dependence of scattering from sea surface on incident angle and wind speed is analyzed. The coupling effect of composite time domain electromagnetic backscattering from a target and sea surfaces is analyzed based on ray tracing and time domain physical optics. The characteristics of backscattering from dihedral reflector are calculated. The wide band RCS is in agreement with the theoretical results, showing the high efficiency and practicality. The time domain composite electromagnetic scattering field of large plate above sea surface is calculated based on the method here. And the influence of incident angle on backward far field is analyzed.
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