Dual band circularly polarized CPW monopole antenna inspired by metasurface reflector

Abstract

A high gain, dual-band circular polarized coplanar waveguide (CPW) patch antenna with a metasurface reflector was proposed and demonstrated in this paper. Using a FR4 substrate with a 0.8 mm thickness, an asymmetrical ground plane was made for a CPW patch antenna. The proposed antenna exhibited dual-band characteristics having reflection coefficient (S11) below − 10 dB from 1.70 GHZ to 3.02 GHz with a bandwidth of 52.38% and 4.59–6.69 GHz with a bandwidth of 42.16%. The average gain was 3.2 dBi in the lower band & 2.5 dBi in the upper band with 3 dB axial ratio of 27.1% bandwidth in a lower band. A metasurface reflector was placed along the proposed antenna with foam as a dielectric between them to increase the gain and bandwidth. The antenna, when combined with the metasurface reflector, achieved an impedance bandwidth of 37.8% in the 1st band, 63% in the 2nd band and both the bands exhibits circular polarization with a 3 dB axial ratio of 57% in the 1st band and 33.02% in the 2nd band. The average gain was 7dBi, with a maximum gain of 7.9dBi at 2.4 GHz. A prototype of an antenna & metasurface reflector was fabricated and measured results were found to be good in comparison with simulated results.