Low-Profile Circularly Polarized Metasurface Antenna

In this paper, a metasurface antenna with circular polarization is demonstrated for low profile. The proposed antenna is comprised of two layers, including a metasurface layer and a feeding layer. The antenna is excited by the square patch with a tilted slot for circular polarization. The square patch is connected to a coaxial inner connector. Using the metasurface, the antenna's profile is $\boldsymbol{0.039}\lambda_{0}(\lambda_{0}$ is the free-space wavelength at 5 GHz). The overlapped axial ratio and impedance bandwidth is 16% (4.6-5.4 GHz) with a gain of 8.4 dBic.