Study on the electromagnetic scattering from a conducting plate above the time-dependant sea surface

Using current numerical techniques to evaluate the electromagnetic scattering between a time-dependant sea surface and a target, due to varying with the time, the elements of the impedance matrix and the surface electric current of the sea surface must be re-evaluated at different moment. Therefore, vast memory and computational requirements are required. In order to overcome this problem, in this paper, the surface electric current of the conducting sea surface and the first-order scattering from the conducting plate are obtained by employing Physic Optics (PO) method. The backscattering field of the time-dependant sea surface is calculated by using Kirchhoff Approximation. Meanwhile, taking the advantage of a newly developed technique that utilizes the reciprocity theorem, the difficulty in formulating the secondary scattered fields from the composite target is reduced. The dependences of the backscattered field on the parameters, such as the wind speed and the sizes of the plate are discussed. In addition, a model is formulated for Doppler spectral shift of the coupling field, and the characteristic of the Doppler spectrum of the composite backscattering field is analyzed in detail.