Graphene-controlled reconfigurable patch antenna using shorting elements

This paper reports the design of a patch antenna that uses of graphene-based shorting elements to implement advanced functionalities, such as multi-band and beam-steering, which make it extremely attractive for the future Fifth-Generation (5G) wireless networks. The proposed structure has 36.75×29.25 mm2 size and it has been designed on a Rogers RT/duroid 5880 substrate, 1.58 mm thick. It is composed by an external slotted rectangular patch that contains an internal circular shape. The internal shape is separated from the external one by a circular slot but it is linked to it by four copper bridges short-circuited to the underlying ground plane through a thin metal pin, one for each bridge. It has been shown that the multi-band and the beam-steering functionalities are strongly affected by the geometric location of the shorting pins. By controlling the connection of the bridges perpendicular to the antenna length, the direction of the antenna main lobe can be changed. By using the Finite Element Method (FEM), the geometric location of the shorting pins has been optimized so that the antenna resonates at 3.5 GHz frequency, exhibiting a 6.6 dBi maximum gain and a-17.55 dB S11 parameter. Moreover, by controlling electronically the connection of the shorting elements using graphene foils, three distinct beams, steering between-22 to +22 degrees, have been obtained. The beams show about 1.4 dBi theoretical antenna gain using graphene foils with 20 Ω/sq sheet resistance.