Beam reconfigurable antenna for the THz band based on a graphene high impedance surface

In this paper a reconfigurable beam antenna is proposed for THz applications, based on a switchable Graphene High Impedance Surface (G-HIS) that acts as a reflector for a primary radiator. The Graphene-HIS structure composed of two layers of graphene cells arranged in a 5×5 array, the two planes of the array are separated by a thin silicon oxide layer; patches in the same row are connected together, to be biased by a common DC voltage to the entire row; this gives the ability to control the graphene conductivity σ. The results show that the shape of the radiation pattern can be changed by changing the voltage applied to each row of G-HIS array. The antenna was fabricated and characterized using a THz-TDS laser system. Measurements are in good agreement with simulations as far as the graphene surface impedance and the resonance frequency are concerned. The scanning reflection on the antenna surface due to the change on the applied voltage is presented to show the effect of biased graphene layer on the dipole properties