| It is well known that modern war is not a certain area,military action against both sides,but a full range of information war,which is an electronic countermeasure consisting of electronic reconnaissance and anti-reconnaissance,electronic interference and anti-interference,and electronic stealth and anti-stealth.Usually it is mainly attacked by aircraft loaded with ammunition,supplemented by military operations,and backed up by advanced military technology in warfare.In order to improve the battlefield survivability and penetration ability of weapon systems,radar stealth technology has gradually become a research hotspot.Among them,reducing RCS of antenna system without affecting the radiation performance has become the key research direction of radar stealth technology.If only a single station of stealth,traditional bandpass frequency selective surface(FSS)radome frequency selective filtering can be achieved,the FSS can allow a certain frequency band signal,and the threat of other frequency wave is reflected to stay away from the direction of the wave,but in the face of the double(multiple)radar,the base station by the reflected wave will be detected,not only short of invisibility effect,but will increase the radar scattering cross section area of the antenna system(RCS).In this paper,a periodic structure with in-band and out-of-band absorption effect is studied and applied to the design of radar stealth radome.The stealth radome can make the signal pass well in the working frequency band of the antenna.In the non-working frequency band of the antenna,it can absorb electromagnetic wave,so as to achieve good stealth of the antenna system.First study square ring resistance film absorbing body potter absorption,this wave absorption by the body upper square ring resistance of the film,in the middle of the low-loss dielectric and metal plate of the lower layer,through the selection of loading frequency on the metal board unit,implements the wave 1 GHz,4 GHz to 13.5 GHz can reach at least 10 db absorbing effect of plane wave radome and 20 GHz,in 4.4 GHz to 13.8 GHz and 25 GHz-32 GHz frequencies can achieve at least 10 db absorbing effect of plane radome;Then,the absorbing characteristics of the absorber integrated by lumped resistors are studied.The K/Ku dual-band band transmission is realized by loading the double-broadband band-pass FSS on the metal reflector in the lower layer,and the 7.4GHz-11.7GHz can achieve at least 10 d B absorbing effect.The plane lens array is loaded on a corrugated horn Shared by both frequency bands,forming a plane lens antenna operating in the wave transmitting band of AFSS,The planar lens array converts the spherical wave front of the electromagnetic wave radiated by the horn antenna into the planar wave front through phase compensation,or focuses the incident electromagnetic wave in any direction in free space in a region behind the lens,and then receives the electromagnetic wave through the feed antenna,which will greatly improve the efficiency of the horn antenna.By properly integrating the upper impedance surface with the lower dual-band bandpass FSS on the hexagonal planar periodic structure,it is more suitable for the array element of the hemispherical radome while maintaining the performance of the cell. |
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