Y-shaped graphene-based antenna with switchable circular polarization

In this paper, an antenna with the ability to provide the right- and left-hand circular polarization in the THz band is presented. The central frequency of the antenna is set at 0.45 THz according to the proposal requirements. The antenna structure is designed to control its polarization rotation by adjusting the graphene conductivity with chemical potential changing. Two symmetric orthogonal arms of antenna are key point of proposed structure. By controlling the chemical potential of each arm, this capacity is created to control the conductivity of them. With this control, phase transposition between the two orthogonal arms is obtained. This precedence or delay of the phase is regulated by the chemical potential changes of the antenna arms, which results in a 90 degrees phase difference between them. By moving the phase of each arm, two right- and left-hand circular polarization patterns is realized. In the frequency range of 0.42-0.48 THz the axial ratio less than 2.15 dB is reached in the antenna axis direction. Whereas the S-11 is less than -12 dB for the aforementioned frequency range.