| Passive jamming technology has become an important branch in the field of electronic warfare,constantly innovating and improving with the development of modern military technology.Among them,resonant chaff jamming,as an important passive jamming method,has been quite mature in research and application.In order to further reduce the volume and weight of interference devices,it is necessary to conduct in-depth research on the scattering characteristics of smaller electrical size interference and explore potential methods to improve interference effectiveness.In this regard,this paper studies two methods to enhance the electromagnetic wave interference ability of micro-nano particles: one is to enhance the absorption of electromagnetic waves by electrically charged dielectric particles with ultra-small electric size;the other is to enhance multi-mode resonance scattering by structural design for sub-wavelength particles with medium electric size.The main research contents are as follows:(1)Study on electromagnetic extinction characteristics and charged enhancement of electrically small particles.When electromagnetic waves propagate in a particle system,phenomena such as reflection,refraction,diffraction,and fluorescence occur,which can affect the propagation of electromagnetic waves and cause attenuation,thereby achieving electromagnetic shielding interference.Based on Mie theory,an electromagnetic scattering model for electrically small particles has been established,and the electromagnetic response of particles with different surface charge densities in macroscopic electrically neutral conditions and when carrying charges has been analyzed.Simulation calculations of extinction coefficient,scattering coefficient,absorption coefficient,and backscattering coefficient before and after the particles are charged have been conducted to study the enhancement effect of charged particles under different conditions.The results show that the shielding(extinction)effect of particles on electromagnetic waves is significantly enhanced when the particle surface carries a certain amount of net charge,which is a potential and efficient form of electromagnetic interference.(2)To effectively evaluate the macroscopic electromagnetic interference performance of charged particle clouds,a simulation software for electromagnetic shielding characteristics of particle clouds was developed.The Monte Carlo method was used to simulate the multiple interactions between electromagnetic waves and charged particles in the particle cloud to obtain accurate radiation transmission characteristics of electromagnetic waves in the particle cloud.The numerical analysis investigated the influence of charge density,particle radius,and cloud mass concentration on the transmittance of electromagnetic waves,and using the Monte Carlo method to obtain simulation results closer to the actual than the particle independent scattering model.Based on radar equations,the radar maximum detection range was used to evaluate the interference effect of the particle cloud system.Finally,a simulation software for calculating the electromagnetic shielding effect of charged particle clouds was developed using MATLAB,which can calculate various characteristic quantities such as the scattering characteristics of individual charged particles,multiple scattering attenuation of the clouds,and radar detection distance reduction.The simulation results verified that the charged particle cloud system can effectively shield and interfere with enemy detection radars.(3)Research on enhanced multiple-mode resonance scattering of subwavelength dielectric particles with medium electrical size.Microstructural reshaping is carried out on subwavelength spherical and ellipsoidal dielectric particles,and the influence of their resonant modes on the scattering characteristics of particles is analyzed.The enhancement of radar scattering cross-section and bandwidth extension is achieved through multi-mode splicing.It provides a new idea for the research on the new structure of passive electromagnetic interference. |
