Low Sidelobe Antenna Based on Single-Substrate Transmissive Metasurface

In this article, a transmissive metasuiface(MS) that can independently control the transmission phase and amplitude of linearly polarized wave is proposed. The MS element consists of a single-substrate and two layers of metal. It achieves 360° phase coverage while maintaining high transmission amplitude. Based on the element, a phase-modulated MS antenna operating at 14.5 GHz is designed, achieving a high gain of 21.7 dB. Building upon the first antenna, amplitude modulation is used to improve the sidelobe level (SLL) of the $\boldsymbol{yoz}$ plane. Compared with the phase-control MS, the amplitude-phase controlled MS attains approximately a 6 dB SLL suppression by sacrificing a 1.4 dB main-lobe gain. The proposed MS offers advantages such as simple structure, low profile, and high gain.