Circularly Polarized Pattern Reconfigurable Antenna using Coding Metasurface

In this paper, a circularly polarized pattern reconfigurable antenna operating at 3.5GHz is presented. The proposed antenna consists of a dual-feed antenna as a source and $7 \times 7$ coding metasurface as a superstrate. The feeding position of the patch antenna is orthogonal to each other and optimized to generate good circular polarization. The unit cell utilized in coding metasurface exhibits transmissive characteristics for dual-polarized incident waves, with its structure consisting of an even-loop and a diagonal strip. Three PIN diodes are placed on the unit cell to control overall emission. The proposed antenna performance is evaluated in nine distinct modes of operation. The antenna achieves circularly polarized beam steering from -18° to +22° in the $y z$-plane. In each beam steered direction axial ratio is less than 3-dB. The antennas overall bandwidth is from 3.48 to 3.56GHz with peak gain of 3.49dBic.