A novel high-gain circularly polarized planar lens antenna based on the element rotation method

A novel high-gain circularly polarized planar lens antenna which is designed based on rotated elements is proposed. We use these rotation elements to design a circularly polarized transmission focusing planar phase-gradient metasurface (PPGM). By changing the angle of the metal patch on the element gradually, we can obtain the required transmission phase shift for PPGM. Based on the principle of the phase compensation of the optical lens and the Pancharatnam-Berry phase diffractive optics, the PPGM is designed. The simulation results show that the PPGM can not only realize high efficiency cross polarization conversion for vertical incidence of right handed circularly polarized plane wave, but also transform the quasi-spherical wave emitted by the patch antenna pointed at focal point into plane wave successfully, which can effectively improve the antenna gain. The simulated peak gain at 13 GHz is 18.4 dB and the front-to-back ratio (F/B) is 25.4 dB. The proposed lens antenna has a good performance and can be applied in many communication systems.