Design of a high-gain and low-profile quasi-cassegrain antenna based on metasurfaces

In this letter, a high-gain and low-profile quasi-Cassegrain antenna based on metasurfaces (MS) is proposed. Thanks to the structure of the dual reflectors and the phase compensation technology achieved by MS, the proposed antenna presents a balance between high gain and low profile. This antenna achieves the peak gain of 13.7 dBi, sidelobe level less than -19 dB, and half-power beamwidth of 38° (H-plane) and 28° ( E-plane). At the same time, it has a low profile of 12.6 mm (0.244λ₀) and occupies an area of 132 mm × 132 mm (2.55λ₀ × 2.55 λ₀). The proposed quasi-Cassegrain antenna in this letter provides an alternative for the high-gain and low-profile antenna and also enriches the applications of MS in the microwave band.