Design And Research Of X-band Low RCS Broadband Antenna Based On Metasurface

With the rapid development of electronic industry technology,as the performance of detection equipment becomes more and more superior,the importance of equipment stealth is becoming increasingly prominent.At the same time,the antenna is a component wit h strong scattering ability in the radar system,how to effectively reduce the radar cross section(RCS)of antennas has become one of the important research directions of stealth technology.With the development of electromagnetic technology,a variety of electromagnetic metamaterials with singular electromagnetic properties have been proposed.Compared with the general metamaterials,the two-dimensional sub wavelength electromagnetic metasurface has the advantages of miniaturization and low loss.Because of the good electromagnetic wave control ability,it has been widely concerned and studied,and has been applied to various fields.One of the significant improvements is the reduction of radar cross section(RCS).The introduction of metasurface not only overcomes the limitations of traditional methods,but also improves the performance.Based on scattering theory and metasurface theory,several checkerboard metasurface of artificial magnetic conductor(AMC)and phase gradient metasurface(PGM)are designed and applied to RCS reduction of antenna.The main research contents of this paper include:1.The theory of radar cross section and antenna scattering i s introduced;The principle of RCS reduction of AMC checkerboard structure and generalized Snell's law are introduced and derived respectively for the artificial magnetic conductor and the phase gradient metasurface.2.In this paper,two new types of AMC cell structures are proposed.The two AMC cell structures have the characteristics of reverse reflection phase in a wide frequency band.When the two AMC cell structures are arranged in a10×10 checkerboard,the reflected waves of the two AMCs will interfe re and cancel,which significantly reduces the RCS.A microstrip antenna working in the reduced frequency band is designed and loaded on the checkerboard metasurface to achieve 10 d B RCS reduction in the X-band,which can effectively improve the gain while reducing the RCS and maintain good radiation performance.3.In order to further expand the RCS reduction bandwidth of the metasurface of AMC chessboard,four new AMC cell structures are designed.Based on the array theory and the principle of phasor rep resentation of reflection phase,the number of each cell is optimized by using the algorithm.Several different arrangements of checkerboard structure metasurface are designed,which can effectively broaden the bandwidth of RCS reduction in high frequency part,disperse the scattered electromagnetic energy,and achieve good bistatic RCS reduction.4.Based on the generalized Snell's law,six kinds of PGM elements with a phase gradient of 60° are designed,and eight gradient direction metasurface cells are formed,which are arranged in the form of straight line and spiral respectively.The simulation results show that the spiral metasurface can effectively disperse the scattered electromagnetic energy with good RCS reduction characteristics of monostatic and bistatic.