Novel Polarization Conversion Metasurface for Circularly Polarized Fabry-Perot Cavity Antenna

A sequentially rotated polarization conversion metasurface (PCM) composed by receiver- transmitter unit cell is presented in this paper. There are four receivers and four radiators in each unit cell. The four receivers are rectangle patch with same size and orientation. They can receive the linearly polarized wave at the same frequency. Whereas the four radiator patches are arranged in a sequentially rotated order. Through tuning the sizes of different radiator patches, equal co- and cross-polarization transmission magnitudes with 90° phase difference are obtained. Then the transmission wave of the unit cell can be converted into circular polarization. Besides, the transmission magnitude of the unit cell can be tuned through changing the offset distance of the metalized via hole. So the unit cell can realize the polarization conversion and magnitude manipulation simultaneously. Therefore the MS composed by this unit cell can obtain property of linear to circular polarization conversion with the magnitude control. The simulation results show that the PCM presents well polarization conversion ability. Meanwhile, to verify the magnitude manipulation of the MS, it is designed to present high reflectivity to be applied in Fabry-Perot cavity antenna. and make the antenna obtain high gain. Combined the polarization conversion capability of the metasurface, the Fabry-Perot cavity antenna can obtain high gain and circular polarization performance simultaneously. The simulated results show that the antenna achieves well circular polarization radiation characteristics.