Fig. 5: Experimental results and comparison with simulation.

a, b Reflectance of the brickwork antenna tuneable capacitance metamaterial as a function of frequency: a measurement with gate voltage varied from −160 to 180 V, b numerical simulations of the structure with an air gap ratio of \({r}_{{\rm{air}}}=0.23\) for different graphene conductivities. c THz frequency dependence of the modulation depth. d Modulation speed evaluated from the difference between the DC and AC measurements taken by TDS, as a function of the driving AC sine wave frequency