1 Graphene Quantum Capacitors for High Frequency Tunable Analog Applications Clara F. Moldovan, ϯ Wolfgang A. Vitale, ϯ Pankaj Sharma, ϯ Michele Tamagnone, ‡ Juan R. Mosig, ‡ and Adrian M. Ionescu ϯ ϯ Nanoelectronics Devices Laboratory, ‡ Laboratory of Electromagnetics and Acoustics, Ecole Polytechnique Fédérale de Lausanne, Switzerland Supplementary Information The underlying principle of the quantum capacitance tunability is explained by charge density modulation with voltage as shown in Fig. S1. For voltage levels near the Dirac point the charge modulation is dominated by the effect of the quantum capacitance, while for higher values we observe the conventional linear dependence due to the field effect. Figure S1. Charge density modulation by voltage bias, as obtained by measurements of the quantum capacitance in D1 at room temperature.