The effective electrical permittivity of a graphene monolayer is experimentally investigated in the 5-40 GHz range, which encompasses the microwave and the lower part of millimeterwave spectrum. The measurements were carried out using a coupled coplanar waveguide placed over a graphene monolayer flake, which is deposited on Si/SiO2. In contrast to some initial predictions, the effective permittivity of the graphene monolayer is slightly decreasing in the above-mentioned frequency range and has an average value of 3.3.
@article{arxiv.1309.0990,
title = {Microwave and millimeterwave electrical permittivity of graphene monolayer},
author = {Alina Cismaru and Mircea Dragoman and Adrian Dinescu and Daniela Dragoman and G. Stavrinidis and G. Konstantinidis},
journal= {arXiv preprint arXiv:1309.0990},
year = {2013}
}