Phase- and Amplitude-Control Metasurfaces for Antenna Main-Lobe and Sidelobe Manipulations

The metasurface (MS) antenna is an important microwave component in the communication system due to its unique beam radiation capability. However, current studies mainly pay attention to improve the performance of the main lobe of the MS antenna, leaving the sidelobe unexplored although it is also essential in some practical applications. In this paper, several phase- and amplitude-control reflected MSs have been proposed to simultaneously manipulate the antenna's main lobe and sidelobes. The MSs consist of modified I-shaped particles which can independently manipulate the phases and amplitudes of the cross-polarization waves by changing the split size and orientation, respectively. A focusing phase distribution and different Taylor amplitude distributions have been fixed on the MSs. By illuminating the MSs with a self-made antenna, we have successfully designed four MS antennas. For the first antenna, we solely pay attention to improve the main lobe and achieve a high gain of 20.7 dB at 10 GHz. For the other three antennas, we also aim to manipulate their sidelobes. The resultant sidelobe levels (SLLs) are about -25 dB in the xoz plane for the second antenna, -29 dB in the yoz plane for the third antenna, and both of the former two characteristics for the fourth antenna. Compared with the first MS antenna, the last three antennas suffer from gain reductions of 2, 1.7, and 3 dB, respectively. These proposed MS antennas provide a new way to manipulate both main-lobe levels and SLLs and also greatly promote the integration of MSs and antennas.