A Low-Profile Wideband Metasurface Antenna With Fan-Beam Radiation

This work presents a design of a fan-beam metasurface with a low profile and a wide operating bandwidth. We introduce a new meta unit of four-loop structure which produces high refractive index over the wide operating bandwidth. The metasurface composes of impedance matching layers and core layers to contribute to the fan-beam radiation. A prototype working at X-band is designed, fabricated, and measured. The measured results agree well with simulated ones. The measured results exhibit a wide bandwidth of 51%. The measured fan-beam radiation performances show that the 3-dB beamwidths on E and H-plane are 17. and 45., respectively. The realized metasurface is with the height of about 0.24 $\lambda_{0}$ , where $\lambda_{0}$ is the wavelength at center frequency in free space. Measured realized gain is about 15.6 dBi at center frequency. In addition, the measured cross polarization discrimination is better than 25 dB across the entire bandwidth.