Graphene based microstrip antenna for triple and quad band operation at terahertz frequencies

Abstract

A plasmonic resonator antenna is designed to operate at the lower terahertz (THz) frequency band of 0.5–5 THz. A very thin layer of graphene film about 0.34 nm is employed as the radiating patch. The resonant frequency of the antenna is controlled by tuning the chemical potential of the graphene layer. As the chemical potential of the antenna is varied from 0 eV to 2 eV, we achieve additional resonant modes leading to triple band operation. At a fixed chemical potential of 2 eV, quad band operation is realized for a substrate thickness of 45 μm. It is inferred that, the operating frequency of the antenna can be varied based on the requirement, by tuning the chemical potential of the graphene layer and by modifying the substrate thickness. For the single band antenna operation, a maximum gain of 2.58 dB and directivity of 2.89 dBi is obtained at 2.58 THz. In the case of triple band operation, a maximum gain of 1.22 dB and directivity of 3.66 dBi is obtained at 4.41 THz. Further, quad band operation is achieved at 1.73 THz, 2.6 THz, 4.01 THz and 4.72 THz, with a maximum gain of 1.61 dB and a directivity of 7.17dBi at 4.72 THz. Further, the effect of chemical potential on the main lobe direction of the radiation pattern, leading to beam steering, is also investigated for the first time.