Scattering Properties Of Poly-dispersed Small Spheroid Particles Under Normal Distribution Of Their Rotatory Axes

This paper has studied the mean attenuation, scattering, and back scattering cross sections of groups of small rotating spheroids about characteristics of microwave scattering when their rotatory axes are oriented at random in any direction in 2D plane and 3D space respectively under the condition of normal distribution, and that those physical quantities are changed with different variance, expectation and wave lengths of incident electromagnetic wave. By driving expressions and using the method in numerical integration, the results of numerical calculations are analyzed, discussed and contrasted with different conditions, and they showed that there are evident differences in the mean attenuation, scattering, and back scattering cross sections of oblate spheroid particles when the variance is so small that it is near to zero namely it is the same as the rotatory axes are parallel with one direction and when H-polarized and V-polarized incident waves happened. These differences are depended on the relative differences in the average orientation of rotatory axes and the polarized directions of incident wave. With the increase of variance, the difference in H-polarized or V-polarized incident wave and in the different mean cross sections is becoming gradually small until when the variance is infinity namely the rotatory axes of the group are uniformly oriented: at this time the different mean cross sections are independent of the polarized status of incident wave. Symmetries are existed in oxy and oyz planes for horizontally and vertically polarized waves, i.e. one's H-polarized case is the same as the other V-polarized one. While the expectations of the rotatory axes oriented in oxz plane are complement, one's H-polarized case is the same as the other V-polarized one.It is also found by comparing with different mean cross sections that there is similar variability for the mean attenuation and scattering cross sections as a function of the different variance, expectation and the wave lengths, but there is much difference for the mean scattering and back scattering cross sections especially when the rotatory axes are oriented randomly in normal distribution in oxy plane or oyz plane and 3D space .