Research On The Method Of Reducing Radar Cross Section In Broadband

With the rapid development of radar detection technology,higher radar stealth techniques are required in modern military operations.The key to stealth technology is to reduce the RCS of protected objects.As a strong scattering source,suppressing the RCS of antenna has become the key of stealth technology.In the face of the increasingly complex electromagnetic environment on the battlefield,the traditional stealth technology can’t meet the demands.As a new type of functional material,metamaterials can flexibly control electromagnetic waves and be easily combined with antennas,which is the focus of current research on RCS reduction.According to the theory of absorption and phase cancellation,RAM and PCM are designed in this paper,and applied to reduce the broadband RCS of antennas.The main research contents are as follows:1.Depending on the stealth theory of wave absorption,a broadband RAM is designed based on loss mechanism.Through the combination of circular ring and square ring metal sheet,a double resonant structure is formed,and the overall impedance is adjusted by the loading of lumped resistance,so as to achieve good absorption of electromagnetic wave in6.5-12.5GHz.In order to test the absorption of RAM,the microstrip antenna is periodically surrounded by RAM units.Simulation and measurement proofs that the directivity of the antenna is significantly improved,and the RCS of antenna is average reduced by 10.2 d B in7.4-17.0 GHz.In particular,the peak reduction reaches 23.5 d B at 7.7 GHz.2.Depending on the stealth theory of phase cancellation,a broadband and highefficiency PCM structure is designed.The PCM etches open ring slits at the center of the hexagonal patch to form a three-resonant structure,and uses two different dielectric substrates to adjust the overall input impedance.It can achieve a polarization conversion effect of more than 90% at 7-17 GHz.When electromagnetic waves incident on PCM and its mirror structure,the reflected waves are cancelled out or scatter to non-threatening area,so that the backward RCS are reduced.By means of surface current analysis,PCM structures are reasonably arranged around the laminated microstrip antenna,and metal defect ground is used to improve the antenna gain.The radiation performance of this antenna is improved in the operating band,which the peak gain increases from 4.78 d B to 8.23 d B.Meanwhile,the design antenna achieved excellent RCS reduction in 8-21.6 GHz,and the in-band reduction is more than 12.2 dB.