Design of Bidirectional Same-Sense Circularly Polarized Antenna Using Metasurface

This paper presents the design of a bidirectional same-sense circularly polarized (CP) antenna using the metasurfaces. The antenna is composed of two metasurfaces and a ground plane with etched slot sandwiched between the two substrates. Each metasurface is made up of an array of $2\times 4$ corner truncated patches placed back-to-back at the top and bottom of the antenna. The antenna is fed by a 50 $\Omega$ coplanar waveguide. The antenna radiates same-sense right-hand CP waves in both the front and back directions. It has overall dimensions of 48 mm $\times 24$ mm $\times 3$ mm ($0.91\lambda_{0}\times 0.45\lambda_{0}\times 0.05\lambda_{0}$ at 5.7 GHz). The $|\text{S}\text{l}1|\lt -10\text{d}\text{B}$ impedance bandwidth is 5.21-6.26 GHz (18.4%) and a 3-dB axial ratio (AR) bandwidth is 5.36-6 GHz (11.2%) for both front and back directions. The antenna gain is 3. 0-5.29dBic for both directions within its AR bandwidth.