A circularly polarized graphene based wideband 1 × 2 array antenna for terahertz spectrum applications

A graphene-based 1 × 2 array antenna with circular polarization for terahertz applications is prescribed in this article. Initially, a novel concept of a folded quarter wave impedance transformer is utilized in the design process of a single element for minimizing the overall antenna size. The opposite corners of the patches have been truncated and structural modifications are performed with the insertion of four flower-shaped slots along with an additional circular slot for achieving a much-improved reflection coefficient and better impedance bandwidth. It also shows a much wider 3 dB axial ratio bandwidth, confirming circular polarization due to the suggested modifications in its geometry. Then, an array antenna has been formed to provide better gain. The configured patches are fed by a magic-T power divider to attain the required impedance matching. The results of the CP antenna array have been analyzed using the HFSS and CST simulators. The propounded 1 × 2 array antenna shows circular polarization with a 3 dB AR bandwidth of 205 GHz (2.345-2.55 THz) and wide spectral coverage of 210 GHz (2.345 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>-</mml:mo></mml:mrow> </mml:math> 2.555 THz) along with a maximum gain of 8.65 dB and 99.8 % radiation efficiency with a total size of 53.5 × 102 × 1.56 μm³. It could be utilized for high-speed data transmission, material characterization, terahertz spectroscopy, terahertz imaging, etc. applications.