Research On High Performance Wide-Band Stealth Radome

Although traditional radome can protect antennas in configuration and electromagnetic performance,the radome still generates electromagnetic coupling with the antennas,which will absorbs and reflects the electromagnetic wave radiated by the antenna.All of these will cause interference and damage to the half-power beam width,bandwidth and maximum gain,and these problem even lead to the breakdown of the military communication system.In addition,with the rapid development of electronic technology,the ability of military radar detecting system also improves in finding specific goals and achieving precise positioning.Large antenna arrays such as phased arrays,are often used in modern military systems,which will make RCS increase and exposure our targets.So it is necessary to study a new Frequency Selective Surface absorbing radome(FSR).It is not only transparent to the incident electromagnetic waves in the antenna operating frequency,but also can efficiently and stably absorb the detection signals at a large angle and wideband or even completely absorbs the reflected signals.Based on the great military significance of the stealth radome,this thesis proposes several new Frequency Selective Rasorber designs with in-band transmission and outband absorption performances,which have wide range of applications.This thesis describes the whole research process including theoretical analysis,designs of absorbing structure,design of FSS,overall design of FSR,optimization algorithm,error analysis,measurement,and improvement.The structure of this thesis is as follows:Chapter ? focus on the current development of stealth radomes,and summarizes implementation methods available and the advantages and disadvantages of each structure.Finally the chapter arrangement of this thesis is introduced.Chapter ? in this chapter,mainly introduces the basic theory and methods to realize FSRs,including the basic theory and parameters of FSS,transmission line theory and parameters,and the relevant theory and calculation formulas of circuit analog absorption,which provide theoretical basis for the design of FSR.Chapter ? introduces differential evolution algorithm in order to provide an optimization method for the subsequent complex FSR design and reduce unnecessary work.Then the equivalent circuit analysis methods of FSS and the related calculation formulas are given.A simple FSR model was used to verify the formula,and the accuracy and validity of the analysis method were verified by comparing the results of optimization and simulation.Finally,the interdigital structure was used to realize better performance of FSR.Chapter ? the complete design process of FSR is presented.The single-layer,double-layer,three-layer and four-layer resistor film structures were analyzed respectively.Meanwhile,FSS with the wideband and low-loss was proposed.Finally combine the obtained absorbing structure and FSS to design a new FSR.It solves the problem that the performance of absorbing structure and FSS is better than the performance of composite structure.Chapter ? summarizes this thesis,and puts forward the corresponding solutions to the deficiencies in the work and the areas that need to be improved.