| Study on the Composite electromagnetic scattering properties of the sea and the targets at a distance above the sea exists widely used in ocean microwave remote sensing, target identification and monitoring of maritime and sea monitoring, etc. In this paper, a hybrid method which combines time domain integral equation(TDIE) with time domain Kirchhoff approximation(TDKA) is presented to solve the problem of the composite electromagnetic scattering properties of one-dimensional sea surface and the two-dimensional conductor target. The main contents are displayed in the following:1. Several different methods of electromagnetic scattering are described. By introducing the method of moments leads to corresponding time domain calculation method, namely time domain integral equation method(TDIE). Provided time-domain integral equations of two different one-dimensional targets and the method of target modeling and data processing.The current response varying with time on a certain point of two different targets is calculated and the result is well contrasted with the classic accurate numerical methods MOM.2. The current response and far-field scattering of two-dimensional conductor target using the time domain integral equation methods are studied. Modeling and split method of two-dimensional conductor target as well as corresponded calculation method of transient far field at different incident are given. The variation of current response of different targets, backscatter field and scattered field in the specular direction with time are calculated. The variation of current response of the targets with different size, backscatter field and scattered field in the specular direction in different incident angles with time are analyzed. The calculated results are well compared with the method of MOM combined with inverse discrete Fourier transform.3. The electromagnetic scattering properties of one-dimensional sea spectrum are analyzed. Simulated different one-dimensional sea spectrum using Monte Carlo method and numerical calculation is conducted applying time domain Kirchhoff approximation. The electromagnetic scattering characteristics of sea spectrum in different wind speeds,different incident angles are discussed. The electromagnetic scattering characteristics of one-dimensional sea surface using the method of MOM combined with inverse discrete Fourier transform are studied. The results of both methods coincide with each other.4. Electromagnetic scattering of conductor target and PM sea spectrum are studied. Electromagnetic scattering of several different targets and PM sea spectrum in different incident are introduced. Electromagnetic scattering characteristics of target and sea spectrum in different wind speeds, different target sizes, different distances, different angles of incidence, namely the variation of backscatter field and scattered field in the specular with time are given. Studied the electromagnetic scattering characteristics of one-dimensional sea surface using the method of MOM combined with inverse discrete Fourier transform and the result is well. |
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