Low-Profile Dual-Band Superstrate Antenna Using Metasurface
A low-profile superstrate antenna operated at dual-band is proposed using a metasurface (MTS). In order to design the proposed antenna, the MTS as a partially reflective surface (PRS) has a zero degree reflection phase at dual-band and is composed of a substrate, periodic metallic square patches, and rings on one side and periodic metallic meshes on the other side. To satisfy the resonance condition of Fabry-Perot cavity (FPC) at a certain frequency and height of PRS from the ground plane, the reflection phase of the MTS should be controlled by the dimension of the substrate, square patch, square ring, and mesh. In this paper, the planar radiator having a ring patch and a rectangular patch is employed and designed to operate at 2.1 GHz and 5.8 GHz. Also, the height of MTS from the ground plane is 12 mm, which corresponds to about 0.08λ0 and 0.23λ0 at operation frequencies of radiator, respectively. As a result, the gain improvements at 2.1 GHz and 5.8 GHz are measured to be 4.1 dB and 3.2 dB, respectively.