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Modeling of bistatic scattering from an underwater non-penetrable target using a kirchhoff approximation method

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Defence Technology（防务技术） 2022年第7期18卷 1097-1106页

作者： Bin Wang Wen-huan Wang Jun Fan Kai-qi Zhao Fu-lin Zhou Li-wen Tan Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration State Key Laboratory of Ocean EngineeringShanghai Jiao Tong UniversityShanghai200240China

A numerical triangulation and transformation into the time domain of a kirchhoff approximation(KA)method is proposed for the modeling of bistatic scattering from an underwater non-penetrable *** time domain solution in this approximation can be split up into two parts:the solution of reflected field,contributing around the specular direction,and the solution of shadow radiation,contributing around the forward *** average solution in the time domain satisfying the reciprocity principle is *** solution is expressed in terms of non-singular *** proposed method is validated against a normal mode method for bistatic scattering from a rigid ***,the reflected and shadow highlights on the surface of the sphere are shown to verify the integration surface of the reflected field and shadow *** is also tested against a finite element method and an experiment involving a scaled Benchmark Target Strength Simulation Submarine *** time-angle bistatic spectra for the model are evaluated by the direct and transformed average solutions of KA,and the former accelerates its speed of *** results are good,and show that this method can be used to predict the bistatic scattered field of a non-penetrable target.

关键词： kirchhoff approximation Bistatic scattering Time domain Reciprocity Experiment

Microwave Doppler spectra of sea return at small incidence angles:specular point scattering contribution

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Chinese Physics B 2010年第8期19卷 384-390页

作者：张彦敏王运华赵朝方 Department of Physics Ocean University of China Ocean Remote Sensing Institute Ocean University of China

It is well known that the sea return echo contains contributions from at least two scattering mechanisms. In addition to the resonant Bragg scattering, the specular point scattering plays an important role as the incidence angle becomes smaller （≥ 20°）. Here, in combination with the kirchhoff integral equation of scattering field and the stationary phase approximation, analytical expressions for Doppler shift and spectral bandwidth of specular point scattering, which are insensitive to the polarization state, are derived theoretically. For comparison, the simulated results related to the two-scale method （TSM） and the method of moment （MOM） are also presented. It is found that the Doppler shift and the spectral bandwidth given by TSM are insufficient at small incidence angles. However, a comparison between the analytical results and the numerical simulations by MOM in the backscatter configuration shows that our proposed formulas are valid for the specular point scattering case. In this work, the dependences of the predicted results on incidence angle, radar frequency, and wind speed are also discussed. The obtained conclusions seem promising for a better understanding of the Doppler spectra of the specular point scattering fields from time-varying sea surfaces.

关键词： Doppler spectrum specular point scattering sea surface kirchhoff approximation

Fractal characteristics investigation on electromagnetic scattering from 2-D Weierstrass fractal dielectric rough surface

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Chinese Physics B 2008年第8期17卷 2956-2962页

作者：任新成郭立新 School of Science Xi'dian University College of Physics and Electronic Information Yan'an University

A normalized two-dimensional band-limited Weierstrass fractal function is used for modelling the dielectric rough surface. An analytic solution of the scattered field is derived based on the kirchhoff approximation. The variance of scattering intensity is presented to study the fractal characteristics through theoretical analysis and numerical calculations. The important conclusion is obtained that the diffracted envelope slopes of scattering pattern can be approximated as a slope of linear equation. This conclusion will be applicable for solving the inverse problem of reconstructing rough surface and remote sensing.

关键词： dielectric rough surface 2-D band-limited Weierstrass fractal function fractal characteristics kirchhoff approximation

A Study on Radar Cross Section of the Two-Dimensionally Fractal Rough Surface

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Wuhan University Journal of Natural Sciences 1999年第2期4卷 74-77页

作者： Gao Ming-qin Zhang Yuan-qiao Xu Peng-gen Peng Jin-sheng

The analysis of the RCS from the rough sea and ground surface is made. The two dimensionally band limited fractal function is used to model the sea and ground surface, the scattered electromagnetic field is calculated by using kirchhoff approximation. The validity of this result is assured by some references, which indicates that the methods are reliable.

关键词： RCS rough surface two dimensionally fractal function kirchhoff approximation

FRACTAL CHARACTERIZATION OF ELECTROMAGNETIC SCATTFRING WAVES FROM ROUGH SEA SURFACES

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FRACTAL CHARACTERIZATION OF ELECTROMAGNETIC SCATTFRING WAVES...

Numerical study on two circle void flaws in cylinders

1998 International Conference on Microwave and Millimeter Wave Technology

作者： Jihuan YAO Yidong FANG Jingming XIAO Debiao GE Physics department Xidian University

＜正＞Based on the sea power spectrum a fractal model of equilibrium gravity waves is *** analytical closed-form formulation of scattering coefficient is also *** the fractal dimension of hack scattered wave is extracted by box-counting technique,and its relation with the parameters of sea surface and radar system *** results obtained is useful for target detection on the rough sea surface and remote sensing.

关键词： rough sea surface gravity wave fractal dimension kirchhoff approximation

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Numerical study on two circle void flaws in cylinders