THz Electrical Response of Graphene Antennas

Studies of high frequency electrical properties offer an important route in exploring the under explored unique characteristics of graphene. Here the GHz to THz response of graphene is investigated as a proof of principle concept for use as an ultrawide band patch antenna as part of a graphene based near-field communication system. We show that it is possible to produce a graphene multimode variable surface impedance microstrip antenna with several hundred GHz bandwidth via careful selection of the antenna geometry and substrate, and via engineering the relative contributions of the intra- and interband transitions. For an operating frequency of 2 THz an optimized return loss of -26 dB, bandwidth of 504 GHz and an antenna efficiency of -3.4 dB are calculated. Arising from the circular nature of the antenna structure higher order modes are possible and at 3.5 THz the antenna efficiency improves to -0.36 dB however this is accompanied by a reduction in the bandwidth to 200 GHz. Calculations of the real and imaginary parts of the dielectric constant between 1 and 10 THz have been performed which may be important for metamaterial applications.