Research On Mechanism And Integrated Design Method Of High-Performance FSS Stealth Radome

With the rapid development of modern avionics technology,viability and security of aircrafts are deeply threatened by sorts of advanced detection equipments,new types of radar,precise guided weapons.Antenna cabin is one of three strong scattering sources;its stealth technology is the crucial research topic.At present,the most feasible method of reduce its radar cross section is adopting stealth radome.A series of researches,for example the analysis of microwave transmission and stealth characteristic of frequency selective surface(FSS),the electromagnetic response analysis of FSS on non-developable surface and so on,are carried in this dissertation at the background of urgent demands on fourth-generation aircraft and stealth avionics armament.For the analysis of microwave transmission and stealth characteristic,FSS is classified by the resonant characteristics,and its essential features are expounded.The theoretical models of interaction between transmission and stealth characteristic are established for FSS embeded by infinitesimalelements.The physical mechanism of FSS is carried out through the method of equivalent circuit so as to find out the influencing law of transmission and stealth characteristic.For the electromagnetic response analysis of FSS on non-developable surface,structure characters which may affect the electromagnetic characteristics of FSS are extracted through inverse process from FSS on infinite plane mapping to FSS radome.The analysis method and influencing law of structure characters are fully analysed and summarized.For the design of FSS,two kinds of FSS embeded by infinitesimal-elements are optimized and designed,starting with traditional elements and elements embeded by themselves.The errors of distance and dislocation between layers are analysed.Besides,the cause of grating lobes is studied.Some methods based on stopband suppression,multilayer cascade,loading lumped elements and so on are adopted at FSS to lower the levels of grating lobes and improve the cut-off characteristics.Finally,based on the above researches,the radome with low-RCS shape and traditional characteristics of fourth-generation aircraft is selected as design object.The design methods for the stability of FSS and varying thickness in two directions are proposed for transmission characteristics of radome after deciding the design elements.In addition,the design methods for the low-RCS are proposed for the back of radome after deciding the design considerations and criteria.The related design paremeters are obtained through the integrated design of transmission and stealth characteristic.Then,the whole performance of radome is assessed through simulation calculating.Through the simulation of equivalent plate and radome,the passband bandwidth of radome can cover radar band with excellent transmission characteristic,and the radome has obvious shielding function to out-of-band signals.