Research On RCS Reduction Technology Of Anetenna Based On Metamaterial

With the continuous development of electronic science and technology in the military field,the realization and promotion of stealth technology have become an important part of improving national defense strength in the world.At present,with the deepening of stealth technology research,the stealth design of combat platform has reached a good level to some extent.As an important device for transmitting and receiving signals in the communication system,antenna itself is a strong scattering source.Therefore,in the design of aircrafts and other related weapons,how to effectively avoid the strong scattering effect of antenna,so as to achieve a better overall stealth effect of the target,has become a hot issue.Radar cross section(RCS)is the main index to measure the stealth performance of targets.In the research of aircraft stealth technology,how to reduce the RCS of antenna effectively and avoid the detection of radar receiver has become the focal problem.The traditional method of reducing RCS of antenna mainly focuses on the change of antenna shape.With the gradual development of the research on electromagnetic metamaterial,nowadays,the metamaterial can be obtained by designing the metamaterial unit structure and its arrangement.Using the metamaterial to realize antenna RCS reduction has become a new method in this field.Therefore,based on the contents above,this thesis takes Research on RCS Reduction of Antenna Based on Metamaterial as the topic,and does the following work:(1)A broadband polarization conversion metasurface(PCM)is proposed.By combining PCM with microstrip antenna,an antenna with low RCS characteristics in broadband is designed.In this part,firstly,a candy-shaped unit structure of polarization conversion metasurface is designed.By arranging the unit structure and its mirror structure in a chessboard surface,a PCM with RCS reduction effect of more than 5 d B in broadband(7.12-21.67 GHz)is designed,which is compared to PEC structure of the same size.Secondly,by applying the PCM to antenna design,a microstrip antenna with low RCS characteristics in broadband is proposed.Finally,by the processing and measuring the proposed antenna,the RCS reduction effect of the proposed antenna in the broadband(7.52-22.28 GHz)is verified.(2)RCS reduction of the antenna is designed based on a resistance-loaded broadband radar absorbing material(RAM).Firstly,a loaded resistive radar absorber material is designed.The RAM achieves an good absorptivity of more than 93% in the broadband(5.2-13.8 GHz).Secondly,the designed broadband RAM is applied to the antenna design.The processing and measurement results prove that the RCS reduction effect of the antenna is more than 5 d B in the frequency band of 4.57-14.39 GHz(relative bandwidth more than 103%)without changing the basic radiation characteristics of the antenna.(3)An absorptive frequency selective surface(AFSS)with bilateral absorbing property is designed and its RCS reduction effect is verified.This work is based on the principle of frequency selection surface(FSS)and radar absorber material(RAM).Firstly,a band-pass FSS with complementary cross-slot structure is designed.Then,by combining it with RAM,a kind of metasurface with both absorbing and transmitting properties,namely AFSS,is designed.Differing to most single-side absorbing AFSS,this design has good absorption characteristics(absorptivity is more than 90%)on both sides of transmission band(4.8-6.0 GHz and 6.7-13.9 GHz).Finally,the RCS calculation of AFSS and its corresponding FSS in HFSS and CST verifies the RCS reduction effect of AFSS in broadband.