Research On Some Basic Problems Of Electromagnetic Scattering Of Sand Particle

Researches on the propagation of electromagnetic waves in granular media has a wide range of applications in the fields of medicine,atmospheric science,and physics.There have been a large increase in research activity in the area of the electromagnetic scattering of various particle under different environmental conditions,for example,the impact from the surface net charge,the environmental temperature and humidity.However,there are still some problems that have not been studied.In view of this,the equivalent medium theory and the Mie theory are used to discuss these problems.Firstly,there are two models for solving the electromagnetic scattering characteristics of charged homogeneous spherical particles.They use different surface conductivity models to describe the influence of surface charge on Particles,but their similarities and differences have not been discussed.Therefore,this paper discusses the influence of the charge polarity,the size parameter,radius and refractive index of the spherical particles on the results of the two models,and compares the similarities and differences of these two models.Secondly,based on equivalent medium theory and Mie scattering theory,we discuss the influence of temperature and humidity on the electromagnetic scattering characteristics of sphere particles,we especially analyze the electromagnetic scattering characteristics of dry sand,water-containing sand,ice-containing sand,water and ice coexistence sand.Furthermore,the microwave emission characteristics of moist sand layer is analyzed by using the dense medium radiative transfer(DMRT)theory,and the feasibility of microwave radiometer to retrieve the soil moisture in the desertification land is discussed.Thirdly,in view of the potential applications of microwave and terahertz band radar equipment in dust storm monitoring,the applicability of the equivalent medium theory used at much higher frequencies to solve the electromagnetic scattering characteristics of larger heterogeneous sphere particles is discussed.The analysis mainly focuses on the influence of the incident wave frequency,the ratio between the inside and outside radius of the particle,and the refractive index ratio of the core-shell dielectric.Finally,we summarize the results proposed by this paper and look forward to the future work direction.