In this paper, a hybrid of metal and graphene reconfigurable antenna is proposed for the THz band applications. A metal ring is used as radiator, and the antenna can be tuned by graphene. Graphene as a rectangular strip and two L-shape element add to the environment of central metal ring. Changing the chemical potential of every three graphene element changes the operation frequency band of the antenna. Different states are created by biasing each graphene. In fact, the electrical length of the radiating ring can be changed by biasing the graphene strips, so the resonant frequency and the direction of radiation pattern can be tuned and achieve a frequency and pattern reconfigurable antenna. Considering the frequency range of 0.5–5 THz, that is the most usable frequency range in medical applications, so the proposed antenna designed by initial dimensions that to have the resonance frequency in the mentioned frequency range. The proposed structure is able to reconfigure the frequency in the frequency range of 3.82THz to 5.93THz and has the ability to rotate the radiation pattern with a maximum rotation of 48◦. In different states of antenna, a good impedance matching and suitable gain between 4 and 6dBi are achieved.
