A Novel Stealth Method Against An Over-The-Horizon Radar Based On Coherent Acoustic Waves Destroying The Refractive-Index Gradient In Evaporation Duct

Over-the-horizon radar based on evaporation duct is becoming more and more widely applied into the process of radar countermeasure,especially in military field.At the same time,the stealth method of target based on the evaporation duct environment over-the-horizon radar detection has become the focus of academic attention.The stealth method against Radars is an important branch of the “target stealth”,a hot research field all over the world and one of the main symbol to mirror the national defense power.This paper aims to propose a novel stealth method against the over-the-horizon radar based on evaporation duct,which is different from traditional approaches.It has a great theoretical significance and applicable value to the improvement of the radar stealth method and our national defense capabilities.The main work of this paper are as follows:The channel medium characteristics of electromagnetic wave propagation over the horizon in evaporation duct are discussed,and the mechanism of radar over-the-horizon detection in evaporation duct is studied,and then according to ray tracing theory about the electromagnetic wave propagation direction variation induced by atmospheric refraction index gradient,analyze the propagation mode about electromagnetic wave propagating in the evaporation duct of the over-the-horizon radar.Based on the mechanism of the atmospheric refraction index variation induced by an acoustic wave propagating in the atmosphere and the interference theory of waves,the array-distributed artificial dielectric irregularities of atmospheric refractive index can be obtained.The radio waves' over-the-horizon propagation theory in evaporation duct and computer simulation technology are used during the theoretical investigations mentioned above to examine the validity of the proposed new stealth method by experiment approaches.The theoretical model of stealth method resisting over the horizon radar in evaporation duct is established,and the coherent acoustic sources are designed according to splitting wave front method,standing wave principle and array antenna theory,and the analog system for evaporation duct environment is also designed on the basis of the evaporation duct environment properties.The proposed new stealth method is verified utilize the testing system.The over-the-horizon radar stealth new method proposed in this paper is the close fused innovation of over-the-horizon radar based on evaporation duct,stealth method and artificial modification.It is expected to become a great breakthrough in the maritime targets stealth area,which have a potential application in military and civilian areas.