Design of high-gain dual-band dual-circular-polarised antenna using reflective metasurface

A novel design of high-gain dual-band dual-circular-polarised antenna loaded with reflective metasurface is proposed. The proposed antenna consists of a linear-polarised coplanar waveguide antenna with a polarisation-switched metasurface structure. The metasurface is composed of 25 unit cells arranged in a 5 × 5 layout and each unit cell is a pair of symmetrical semi-circle loop with a diagonal microstrip, which is designed to adjust the axial ratio for dual-band circular polarisation. Simulated result shows that the impedance bandwidth of the proposed antenna is about 63% from 3.8 to 7.3 GHz, and the average boresight gain has a great enhancement of about 4 dBi. The proposed antenna possesses the characteristic of right-handed circular polarisation from 4.15 to 4.45 GHz, while the left-handed circular polarisation is from 5.75 to 6.4 GHz. The simulated and measured results are in good agreement so that the performance of the proposed antenna can be confirmed.