Reconfigurable Terahertz Reflectarray Based on Graphene Radiating Patches

A reflectarray antenna based on graphene radiating patches is proposed for reconfigurable radiation patterns at 1 THz. The all radiating elements of the reflectarray are geometrically identical, and the graphene patches in the same row are connected in series to a particular bias electrode. The phase response of the radiating elements can be controlled by changing the value of the bias voltage due to the property of graphene that its complex conductivity can be continuously steered by applying a dynamical chemical potential, i.e. electric field. For the TE polarization, the simulated phase curve shows that a cycle phase range of 360 degrees is obtained by applying a chemical potential from 0 eV to 1.8 eV, while the magnitude of the reflected field is above 5.6 dB. Based on the phase response, each electrode biasing the corresponding row of graphene patches is accurately programmed to build up the required progressive phase distribution for a particular beam pattern. The numerically simulated field distributions and radiation patterns at different biasing states demonstrate that the designed reflectarray can reconfigure the deflection direction of the normal TE incident plane waves with excellent performance.