The Invention Relates to a Wideband Circularly Polarized Metasurface Antenna

Aiming at the single characteristic of traditional antenna bandwidth and working polarization state, a broadband circularly polarized antenna based on metamaterial surface is proposed. The antenna is composed of a rectangular microstrip antenna and an upper metasurface. The distance between the two is h. The metasurface is composed of $5\times 5$ square metal elements with equiangular structures on both sides. The linearly polarized rectangular microstrip antenna as the feeding antenna radiates linearly polarized electromagnetic waves, and the metasurface converts the linearly polarized electromagnetic waves radiated by the feeding antenna into circularly polarized electromagnetic waves. This paper analyzes the principle of circular polarization after the antenna is loaded with a metasurface. The simulation software HFSS is used to perform parameter scanning and simulation analysis on the antenna with the size of 0.88$\lambda\times 0.88$$\lambda\times 0.04$$\lambda \mathrm{m}^{3}$ and the center frequency of 8.5 GHz. The results show that the impedance bandwidth of the atenna S11 <-10dB is 7. 78$\sim$10.03 GHz (relative bandwidth is 26.47%), and the axial specific bandwidth of the antenna Ar $\lt$ 3dB is 8. 06$\sim$9.91 GHz (the relative bandwidth is 21.76%), and the antenna works throughout. The peak gain in the bandwidth is 9.05 dB. In this design, the linear polarization antenna can be directly converted to a circular polarization antenna by loading the metasurface method. While achieving wider circular polarization bandwidth and higher gain, the antenna basically does not affect other performance, and can be widely used in communication systems, radar navigation and other fields.