Research On The Design Of The Unit And The Optimization Of The Array Element Distribution Of The Checkerboard Metasurface

Radar stealth capability is becoming more and more important in information war.Radar Cross Section(RCS)is an important indicator to measure the stealth capability of weapons.As a stealth technology with excellent performance,the checkerboard metasurface has the advantages of low cost of ownership,convenient modification,and wide working frequency bandwidth,which has broad research prospects.The design method of the existing checkerboard metasurface basic unit is complicated,and the application scenarios are limited.Aiming at this problem,this paper improves the existing pixel-based design method,reduces the amount of calculation in the design process to half of the original,and greatly improves the design efficiency.In addition,the conventional checkerboard distribution cannot avoid the generation of grating lobes,and the angle stability is poor.Aiming at this problem,this paper uses the array theory to explain the reason for the grating lobes generated on the checkerboard metasurface.Based on this theory,this paper optimizes the distribution of the array elements,and finally designs a checkerboard metasurface with good RCS reduction capabilities within 4～10.4GHz.The main content of this paper is as follows:Firstly,the existing basic unit design method has been optimized,and two basic units with a phase difference of 4～10GHz that meet the theoretical requirements are designed.On the basis of the array theory,the radar stealth principle of the checkerboard metasurface is studied.The formula is derived for the conditions that need to be met to reduce the RCS of the chessboard by 10 d B.The indicators of each parameter in the basic unit are simulated and analyzed,and their influence on the reflection phase is studied.The existing pixelized basic unit design method is improved,so that the calculation amount in the design process is reduced to half of the original,and the design efficiency is greatly improved.This paper uses this improved method to combine the full-wave simulation algorithm with the binary particle swarm optimization algorithm,and designs two basic units that meet the theoretical requirements at4～10GHz.Secondly,the distribution of the checkerboard metasurface is optimized.A full-wave simulation is performed on the array elements composed of different numbers of basic units.The performance in the vertical direction and the direction of the grating lobe was compared,and the optimal value of the number of basic units in the design of the array element was found.The reason for the grating lobes generated of the checkerboard metasurface is theoretically analyzed.In order to improve the performance of the grating lobe direction,use the staggered triangular distribution to optimize the distribution of the array elements.Compared with the traditional checkerboard distribution and the new staggered triangle distribution,the performance of the new staggered triangle distribution is better than the traditional checkerboard distribution.Finally selected the staggered triangular distribution as the array element distribution.Thirdly,the performance of the designed checkerboard metasurface is analyzed.The actual measurement results are compared with the full-wave simulation results to verify the validity of the full-wave simulation results.The performance of the designed checkerboard metasurface in different electromagnetic environments is analyzed from the three factors of electromagnetic wave frequency,incident angle,and polarization mode that affect RCS.The checkerboard metasurface designed in this paper has a good RCS reduction ability in 96.9% of the frequency band within 4～10.4GHz,and has good angular stability and polarization stability.