Sub-wavelength Graphene Planar nanoantenna for THz Application

Abstract Owing to unique electronic and plasmonic properties at terahertz (THz) band, two-dimensional nano material graphene make it easy for the design of highly miniaturized ultra-wideband (UWB) reconfigurable THz antenna with simple nano structure at subwavelength scale. In this paper, a sub-wavelength miniaturized UWB reconfigurable graphene circular patch nanoantenna at THz band is reported. The simple structured graphene circular patch nanoantenna provides ultra-wideband of impedance bandwidth of 370%. The propagation of SPP waves in graphene THz antenna enables high miniaturization at THz band. At resonant frequency 0.75 THz, SPP wavelength λSPP of the antenna is 10 times smaller than free space wavelength λ0. Broad side radiation pattern with lower back lobe radiation is found at resonant frequency of the antenna. Moreover, frequency reconfiguration in the antenna is easily achievable by applying external voltage via Fermi energy of graphene. For a comparison propose, copper circular patch nanoantenna of the same dimension has been modelled in this work. Copper circular patch nanoantenna resonates at higher frequency 1.15 THz and provides a very narrow bandwidth. Compared to conventional copper metal antenna, graphene nanoantenna enables high miniaturization, UWB behavior, and easy reconfiguration. The proposed graphene nanoantenna can be promising for UWB THz applications.