脉冲镜反射回波及其表面曲率效应

Sound pulse specular reflection echo and their curvature effect of boundary surface

本文由刚性球目标的回波时域结构与反射面的空间分布之间的关系,研究了刚性目标表面曲率对脉冲镜反射回波波形的影响和棱角反射回波的特性。在高频反射区域,镜反射回波同人射波波形相同;在低频或谐振散射区域,光滑曲率表面的脉冲镜反射回波特征是在主回波后有时间扩展,它是由曲率反射面产生的,称为回波的曲率效应;曲率效应与频率、反射角度有关。棱角是表面曲率的特殊情况,弯曲棱角的传递函数与频率的1／2次方成反比,因此,脉冲反射波形产生畸变,称为回波的棱角效应;直棱角的传递函数与频率无关,反射波形与入射波形相同。

Abstract: In this paper, from the relationship between the time range construct of pulse echo from a rigid sphere and surface distribution, the curvature effect of boundary surface of a target on the wave-form of the specular reflecting echo from the surface and sound reflecting from an edge are studied. In high frequency range, the specular reflection echo have the same wave form as the incident wave, but in low frequency range or resonance scattering range, there is a time expansion of the pulse width after main reflecting echo from smooth curvature surface. Since the time expansion is caused by the curvature surface, it is regarded as the curvature effect, which is relative to frequency and reflective angle. The transmission function of a curved edge is in inverse proportion to 1/2 power of frequency, so the reflective wave-forms have the distortion known as the effect of an edge. But the reflecting wave-forms from a straight edge are the same as impinging wave-forms.