▎ 摘　　要

This paper investigates the radiation characteristics of a Hemispherical- Dielectric Resonator Antenna (DRA) loaded with graphene strips and fed by ridge-gap waveguide (RGW) transmission line for 60 GHz. The RGW unit-cell introduces frequency bandgap from 45 to 92 GHz centered around 60 GHz. A coupling slot loaded with orthogonal oriented cross graphene strips is used to couple energy from RGW line to the hemispherical-DRA. The cross slots are used to control the type of polarization radiated from the hemispherical DRA. Different states of linear and circular polarization are achieved according to the biased/un-biased graphene strips. The hemispherical DRA introduces circular polarization bandwidth of 980 MHz with high gain of 7 dBi. Multiple-input-multiple-output (MIMO) antenna arrays consist of 1 x2 and 2 x2 elements are designed to enhance the total gain and circular polarization performance over the single hemispherical-DRA element. The MIMO arrays parameters such as diversity gain, transmission coefficient, multiplexing efficiency, and envelop correlation coefficient are calculated to meet the 60 GHz applications.