| The Synthetic Aperture Radar is often used to be get SAR images which has high resolution about targets in any conditions. As a category of self-sufficient microwave remote sensors, it exploits the idea of effective synthetic antenna apertures formulated by the movement between the antenna and the target, to successfully solve the dilemma among the requirements of high resolution, large antenna, and short wavelength in radar designing system. It has essential applications in multiple military and civil areas.Conventional SAR simulation algorithms assume that the target generating echo wave has a constant Radar Cross Section(RCS) with a constant value. The phase variation is also often ignored. Such an assumption appears to be simple and lost its accuracy when the real target is electrically large, has multiple reflectors as well as sub-wave length complex structures and resonators. It also does not take into consideration the dispersive property of RCS in the bandwidth of a nonlinear signal. Therefore, conventional simulation algorithms often fail in obtaining accurate imaging of aforementioned targets.The thesis tells a useful methodology and theory, which offers a combination of conventional SAR signal processing algorithms, and time-domain full-wave electromagnetic algorithms. With the time-domain full-wave method, the magnitude and phase of the dispersive RCS within the signal frequency band can be calculated through only one simulation. Compared to conventional SAR processing method, it is able to show distinctive properties of complex targets such size, details of object’s structure and pose. The thesis offers theoretical analysis and numerical validation of this algorithm combining full-wave analysis and SAR signal processing. The accuracy and imaging quality of this method is proved. Such a methodology has a tentative application not only in the simulation of radar imaging of complex object, but also in nonlinear signal design and verification. |
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