Metasurface Antenna Design with Ultra-wideband RCS Reduction

In this paper, two novel Artificial Magnetic Conductor (AMC) structures, based on circular loop patch and substrate, are designed to realize 180 degrees 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.