Theoretical Study Of Effects Of Charged Sandstorm On Microwave Propagation

The effects of bad weather on wireless communication are an objective existence of the universal worldwide problems. Research on the electromagnetic wave propagation characteristics of particulate matter under the condition of natural environment has a very important practical significance, such as radio communication system design under sand environment, remote sensing monitoring and inversion for dust, fog aerosol phenomenon and the research on radiation forcing effect of aerosol. There are a large number of studies shown that:the motional particles (such as dust, rain, snow, fog, haze, etc.) are charged under natural conditions, and it will produce an electrostatic field which will be reached up to the highest intensity of 200kV/m. Some scholars have carried out a large number of theoretical researches and analyzed how the electric charge on the particle surface affect the electromagnetic wave propagation. But there is less discussion on the high intensity of the environment electric field effects the particle optical properties. In view of this, this thesis takes common phenomenon of sandstorm in northwest China as an example, under consideration charged sand and dust storms in the strong electric field environment and other factors of the premise, the main research is based on the scattering process of electromagnetic waves attenuation acted by partially charged sand particles, and discusses the relevant scattering characteristics potentially apply in the sand physics research. The main work is as follows:Firstly, in view of the partial charged spherical sand of the incident electromagnetic wave scattering and absorption problems, based on the polarization surface charge density and Rayleigh scattering theory, we have derived the partial charged spherical sand of incident electromagnetic wave on the scattering field, scattering cross section, absorption cross section and extinction cross section.At the same time under the factors of different charge distribution angle, the surface charge density and environmental field, we have compared sand in the form of the spatial distribution of the scattered field based on the two models.Secondly, under the environmental electric field, the particle differential scattering cross section, particle scattering and absorption and extinction efficiency, radar reflection coefficient have been deduced. We also give the discussion about the effects respectively from the particle surface charge distribution angle, the surface charge density and the incident electromagnetic wave frequency. The results showed that:with the increase of the particle charge distribution Angle and the surface charge density, particle scattering efficiency respectively is changed as in sine function and exponential rule, but its absorption efficiency basic remains unchanged. The effects of incident wave frequency on sand electromagnetic scattering properties as follows:for the different surface charge density, with the increases of the incident wave frequency, sand scattering efficiency increases exponentially, and its absorption efficiency increases linearly. Then, in both two modes, we have analyzed and compared the impacts of the concentration of sand in the sandstorm and the humidity on the electromagnetic wave attenuation characteristic, and discussed the influence of sand particle size distribution on electromagnetic wave propagation.Finally, some discussion about the environmental electric field and the sand concentration for the influence of microwave radar reflectivity are given.