Research On Radar Charactristics Of Electrically Tunable Passive Scatterers

In recent years,with the further development of metamaterials,new ideas have been provided for the artificial adjustment of space electromagnetic waves.Active Frequency Selective Surface is a metamaterial with dynamic control characteristics of electromagnetic waves.For the problem that the existing passive jamming devices' s scattering characteristics are fixed and cannot be controlled in real time,this paper studies the electromagnetic characteristics of AFSS,analyzes its impact on radar characteristics,and discusses the possibility of its application in passive jamming.The main work and innovations of this paper are as follows:(1)Design and analysis of the active frequency selective surfaceIn this paper,a “MU”-shaped AFSS is designed.The reflection performance of the structure is simulated from the aspects of unit structure,dielectric support layer thickness,electromagnetic wave polarization mode,and incident angle by HFSS electromagnetic simulation software.The results show that the structure is a single-polarization responsive structure,which is sensitive to the incident angle of electromagnetic waves,and is able to achieve 40 d B adjustable absorption depth.Besides,this structure's modulation bandwidth is 3GHz wider than the square ring AFSS.Finally,the "Mu" AFSS sample is made and tested for its reflection characteristics.(2)Design and analysis of electrically tunable passive scatterersIn this paper,an electrically tunable trihedral corner reflector based on bow tie AFSS is designed.Its radar cross section is simulated by the CST electromagnetic simulation software.The results show that the electrically tunable trihedral corner reflector can achieve rapid backtracking of electromagnetic waves and has a dynamic regulation effect on its RCS value of 20 d Bsm depth.Finally,the electrically tunable trihedral corner reflector sample is made and tested for reflection characteristics.(3)Analysis of the impact of electrically tunable passive scatterers on radar characteristicsThis paper firstly establishes a mathematical model of the trapezoidal modulation of the electrically tunable passive scatterers,then analyzes its modulation principle for radar signals,and proposes a modulation method called intermittent scattering.Then,the time-frequency characteristics of modulate signals and reflected signals,the impact of different incident signals on the periodic trapezoidal modulated reflected signals,and the impact of intermittent scattering modulation on radar matched filtering performance.The results show that the electrically tunable passive scatterer has the characteristics of dynamic regulation of electromagnetic waves,and the reflected signals modulated by the intermittent scattering can cause false target interference after radar matched filtering.