An Ultra-Wideband Vivaldi Antenna With Low RCS For Radar Stealth Equipment

In today’s information war,stealth technology is very important.Stealth technology is to reduce the probability of our target being found by the enemy’s detection radar by reducing the radar cross section(RCS).For the airborne platform,the antenna is an important system component for receiving and transmitting information.At the same time,it is also one of the most important strong scattering sources for RCS.Therefore,for stealth aircraft,the antenna is required to maintain good radiation performance while radar stealth.Vivaldi antenna,which has the excellent characteristics of planar structure,high gain and directional radiation,is widely used in stealth aircraft.In this paper,Vivaldi antenna is studied from the perspective of scattering and radiation performance.Different methods are used to reduce the radar cross section of the antenna.The specific work includes the following aspects:(1)A low RCS UWB Vivaldi antenna loaded with special-shaped structure is designed.The modification technology is used to reduce the RCS of the antenna.The surface current of Vivaldi antenna at different frequencies is analyzed to find out the parts with weak surface current distribution,and the surface metal of this part of the structure is removed,that is,the rectangular and semicircular slot structure is etched on both sides of the radiation arm,so as to reduce the surface scattering of the radiator,reduce the RCS of the antenna,and the maximum RCS is reduced by 18.5d B.(2)A low RCS UWB Vivaldi antenna loaded with diamond mutual coupling split ring resonators(CSRR)structure is designed.By analyzing the filtering characteristics of CSRR,a rhombic CSRR unit structure is designed and etched on both sides of the antenna metal layer.This structure can effectively reduce the RCS of some working frequency bands.The working frequency band of the antenna is 4.8-11 GHz,and the maximum reduction of RCS is 22.5d B.(3)A low RCS UWB Vivaldi antenna loaded with frequency selective surface(FSS)structure is designed.A bandpass FSS structure unit is designed and etched on both sides of the antenna metal layer.The bandpass characteristic of FSS makes the incident wave in the working frequency band transmit through the metal ground,so as to reduce the RCS of some working frequency bands of the antenna.The working frequency band of the antenna is4.9-11 GHz,and the maximum RCS Reduction is 19.8d B.(4)A Vivaldi antenna of bandpass FSS loaded with photonic band gap(PBG)structure is designed.Rectangular PBG periodic structure is loaded on the dielectric substrate of Vivaldi antenna of bandpass FSS.This structure is used to reduce the scattered wave of the antenna,so as to reduce the RCS of the antenna.The working frequency band of the antenna is 4.8-11 GHz,the maximum reduction of RCS is 19.8d B,and the RCS has a good reduction effect in the whole working frequency band in the range of incident angle of incident wave is 0-40°,which solves the problem of small reduction frequency band of RCS of the first two antennas.In this paper,four different methods are used to reduce the RCS of Vivaldi antenna,and the effectiveness of the design method is verified.The four antennas have certain application value in the field of Vivaldi antenna with low RCS,and provide a reference idea for antenna RCS Reduction in stealth aircraft.