The Analysis Of Ka And Above Frequency Band Signal Depolarization Effects In Earth-space Links

The impact of the depolarization effect that is based on the complex environment of the Earth-Space link restricts the development of frequency reuse technology in the satellite communication system.It leads to the deterioration of the isolation of different polarization channels,which makes the clutter in the communication channel increase,and the electromagnetic interference increases,and the communication system Mutual interference is serious.In order to solve the above problems,this paper mainly studies the depolarization effect characteristics of signals in Ka and above frequency bands of the Earth-Space link.The main contents are as follows:Firstly,it explains the background and significance of the topic based on this thesis,and briefly introduces the development and current research trends of Ka-band satellite communication technology,as well as the research status of the depolarization effect of Earth-Space links in home and abroad,and simply instruct both of the main research content and frame structure.Second,it briefly introduces the depolarization effect of electromagnetic waves from the aspects of physical essence and mathematical model,expounds the calculation theory of depolarization effect of clear-sky atmosphere,atmospheric deposition particles and ionospheric environment,and analyzes the generation mechanism of depolarization effect of different environments.The following chapters lay the foundation for the calculation and analysis of the depolarization effect of the Earth-Space link.Third,in view of the depolarization effect mechanism caused by the clear sky,rainfall,snowfall,and dusty environment,the calculation model and the calculation of the required parameters are determined.It also will illustrate the calculation and analysis of the depolarization effect caused by the complex environment of the Earth-Space link.Fourthly,in order to verify whether the multipath propagation affects the depolarization of the original Earth-Space link when the received signal of the Earth-Space link ground station is affected by the terrain features,the ground simulation test is carried out.The test results show that when the terrain features affect the ground received signal,the multipath can affect the depolarization parameters.In other words,when terrain and ground objects(especially dynamic terrain and ground objects)are within the Earth-Space link Fresnel zone,the calculation results of the depolarization model given in the classical model cannot represent the true result.Therefore,for systems such as satellite mobile services,if frequency reuse technology is adopted,the traditional depolarization model needs to be corrected.In view of this situation,the test experiment is designed.Based on the comparison and discussion of data processing and test results,the correction idea of the calculation model of ground link precipitation depolarization characteristics is proposed.The research results in this paper provide theoretical basis and technical support for the development of Earth-Space link communication technology in Ka and above frequency band,it is meaningful to further understand and master the depolarization effect caused by complex environment.This paper provides a certain degree of theoretical support for engineering application,and has reference value for promoting the development and application of frequency reuse technology of satellite communication system in Ka and above frequency band.