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 (0.244
λ
₀
) and occupies an area of 132 mm × 132 mm (2.55
λ
₀
× 2.55
λ
₀
). 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.