Research On The Application Of Artificial Magnetic Conductor Structure In Antenna Design And RCS Reduction

With the rapid development of modern communication technology,multifunctional and high-performance antennas have become the focus of development in research and practical applications,at the same time,antennas have strong scattering capabilities.How to effectively reduce their own radar cross section(RCS)has become one of the important directions in the research of stealth technology.As a new type of electromagnetic materials,the analysis of artificial magnetic conductors(AMC)structures and their applications in antennas have also become a research hotspot in the microwave field.In this thesis,a detailed study is carried out on the surface of AMC arrays for achieving broadband and high gain antennas,and for reducing radar cross section to improve stealth performance.A bowtie antenna based on AMC and a wideband AMC array and low RCS antenna that can effectively reduce RCS to achieve target stealth are designed.The main research content can be summarized as follows:Firstly,the principle of the same-phase reflection band gap in artificial magnetic conductor structures is introduced.The resonant characteristics of surface impedance are explained through analysis of its equivalent circuit model,and a method for analyzing the reflection characteristics of AMC structures is also provided.Finally,the radiation,reception,and scattering characteristics of antennas are discussed.Secondly,a broadband high-gain bowtie antenna loaded with an AMC structure is proposed.In this chapter,a broadband bowtie antenna operating in the frequency range of2.5～3.63 GHz is designed by loading two branches on the antenna to achieve the goal of broadening the antenna bandwidth.Subsequently,an AMC structure matching the frequency of the antenna is designed and arranged as the ground plane of the bowtie antenna.The results show that the designed bowtie antenna operates in the frequency range of 2.39～3.52 GHz,with a maximum gain of 8.75 d B,which is 7.07 d B higher than the original antenna.The profile height is 0.2λ(λ is the wavelength in free space),and it has the characteristics of broadband and high gain.Finally,based on the property of phase difference in different AMC structures,a method for reducing antenna RCS using AMC arrays was explained.A broadband AMC structure based on slot loading was designed and arranged in two checkerboard surfaces,A and B,with circular AMC unit structures.The results showed that there was a phase difference of 143-217 between the two checkerboard surfaces in the frequency range of 11.35-16.85 GHz and10.59-16.4GHz,respectively.In addition,the checkerboard surfaces were combined with microstrip antennas and arranged around them.Simulation results showed that the low RCS antenna designed in this paper can achieve a 10 d B RCS reduction in a wide frequency band while maintaining good radiation performance and enhancing gain.Finally,the antenna achieved a 10 d B RCS reduction and a 1.04 d B gain enhancement in the frequency range of10.6-17.8GHz.This thesis analyzes the structure of AMC and antenna-related theories,and studies the design of two antennas loaded with AMC structures.The results show that loading AMC structures can improve the radiation performance of the antenna and reduce the antenna’s RCS.