A Super-Wideband Miniaturized Graphene-Based Folded Monopole Antenna

A graphene-based folded monopole antenna with super-wideband bandwidth and a small volume is proposed in this paper. The antenna features a disc-loaded folded cylindrical configuration that mainly consists of graphene-powder and graphene-ink cylinders, along with copper discs. Two primary radiation modes are generated and combined to achieve the desired super-wideband bandwidth. The applied graphene-powder and graphene-ink cylinders serve as crucial radiating and tunable elements, rendering the antenna impedance matched across the super-wideband range. Furthermore, direct current (DC) excitation combined with conducting wires is utilized to improve impedance matching and enhance the operating bandwidth toward lower frequencies. The measured results indicate that the antenna has a super-wideband operating bandwidth across 0.114-0.202 GHz and 0.34-18 GHz (|S11| <-6 dB). The measured antenna peak gains range from -3.75-3.50 dBi. The antenna dimensions can be maintained at 0.006λL ×0.006λL × 0.011λL, where λL is the wavelength in free space at the lowest operating frequency.