Excitation of higher order modes in terahertz antenna using graphene strip

A terahertz (THz) antenna is implemented with a technique of achieving the multiband response by exciting the higher order modes without changing the antenna structure. A patterned triangular shaped THz microstrip patch radiator is designed and numerically analyzed for providing the dual-band response with TM10 and TM20 modes. A graphene strip is applied in the antenna structure which can act as a controller or tuner responsible for the generation and mitigation of resonant modes. The insertion of graphene strip can generate the higher order resonances of TM11 and TM21 mode and antenna response can be attained with dual, triple or four operating passbands by varying the chemical potential of the applied graphene strip. The antenna operation is verified with the electrical equivalent circuit model. Moreover, conical or bi-conical radiation beam can be obtained from the antenna corresponding to the nature of the excited resonant mode.