具有超宽带RCS减缩特性的天线设计

Metasurface Antenna Design with Ultra-wideband RCS Reduction

该文设计了两种人工磁导体(AMC)单元,在8～20GHz的超宽频带内,两种AMC结构能够实现180°±37°的反射相位差,将这两种单元组成棋盘结构时,能够实现入射电磁波的散射场相消,从而在超宽的频带内实现棋盘表面法向雷达散射截面(RCS)的显著减缩。同时,利用超表面天线的概念,设计馈电网络,将设计的AMC结构用做天线,仿真发现在9.08～10.30 GHz的范围内,天线的S11小于–10 dB,可以实现天线的有效辐射。实测结果和仿真吻合较好,因此该文的棋盘结构可以实现具有RCS减缩特性的天线设计。

In this paper,two novel Artificial Magnetic Conductor(AMC)structures,based on circular loop patch and substrate,are designed to realize 180°reflection phase difference in a wide frequency band.These two AMCs’reflection phase property is applied to redirecting the scattering fields of a radar target to reduce its Radar Cross Section(RCS).This method of RCS reduction can be realized by covering with a chessboard surface composed of two proposed AMC structures,so the RCS reduction in a wide frequency band can be achieved as well.Compared with the same-sized metallic surface,this proposed chessboard surface can reduce RCS drastically from 8 to 20 GHz under normally incident waves,and the RCS also can be reduced under obliquely incident waves.Meanwhile,this surface also can be used as antenna.By precisely designing feed network,the metasurface antenna can be designed.This antenna also has a low profile.The simulated impedance matching frequency band is from 9.08 to 10.30 GHz.Excellent agreement is obtained between simulation and measurement for metasurface antenna and chessboard surface.Such method gives a method for integrated design of antenna and metasurface,so the RCS reduction can be achieved,at the same time the radiation properties can be maintained.