The Journal of Engineering (Jun 2019)
Complex forward scattering coefficient for signal characterisation
Abstract
In this study, modelling and characteristics analysis of forward scattering coefficients and echoes are investigated. Traditional ground-target forward scattering signal model has not considered the impact of scattering phase; thus it is not accurate enough for describing air-target echoes. To solve this problem, a novel echo model was proposed based on the analytical deduction of complex forward scattering coefficient. The novel model separately expresses the target scattering characteristics and Doppler, greatly facilitating the theoretical analyses of echo characteristics. Then, theoretical and simulation investigations on the amplitude and phase characteristics of forward scattering echoes were made based on the complex forward scattering coefficient model. Theoretical explanations for the periodical fluctuation of far-field echo amplitude, periodical saltation of far-field echo phase, shadow blocking of near-field echo amplitude, and slow variation of near-field echo phase were given, respectively. Meanwhile, the boundary between near-field forward scattering and far-field forward scattering was quantitatively defined, which laid the theoretical foundation for the corresponding signal processing algorithms. Finally, with CST simulation results the accuracy of the echo model is verified and impacts of objects' real shapes are analysed.
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