Miniaturized switchable beam-steering antenna based on gradient metasurface

In this paper, a miniaturized switchable beam-steering antenna based on gradient metasurface (MS) is proposed. By employing an F-P resonant cavity and a shared gradient MS, the gain is raised and the sidelobe level (SLL) is suppressed. Moreover, the directivity of the beam and the gain are further enhanced by loading a radiation layer etched with radiation patches and metal strips. In addition, the proposed antenna has a small size of 100 × 100 × 12.6 mm3 (2.0 × 2.0 × 0.25λ03) and is capable of effective beam steering in both azimuth and elevation planes. By switching the feeding ports and changing the phase differences between ports, the beam can be controlled electronically. Also, the method of beam-steering is simple, and the generated beams have stable radiation characteristics. The final results indicate when four ports are sequentially excited, the antenna can generate beams pointing at θ = 20° and the gain of the beam is 10.33 dBi. These four beams cover almost 360° in the azimuth plane by switching in four different space quadrants. Meanwhile, an elevation beam steering within a range of ± 32° is achieved by changing the phase differences of the ports under dual-port excitation.