Circularly Polarized Hemispherical Dielectric Resonator Antenna with Graphene slots

This paper proposes and analyses the application of ridge-gap waveguide (RGWG) substrate for enhancing the hemispherical dielectric resonator antenna (HDRA) performance. The RGWG introduces band gap behaviour in the frequency band from 45 to 92 GHz and the HDRA is operated at 60 GHz that is within the bandgap of the RGWG. HDRA is combined with the RGWG substrate by crossed slots, one of these slots is rotated by 45° in clockwise to achieve left-hand CP, and the other is rotated by 135° in anticlockwise direction to achieve right-hand CP. For switching between the crossed slots, graphene material is used. The HDRA design has 0.98 GHz CP bandwidth and 7dBi gain when using single element HDRA structure. To improve the gain and the axial ratio, 2×1 HDRA element is used to enhance the gain and CP bandwidth to 8.31dBi and 1.2GHz respectively.