Tunable graphene/dielectric laminate for adaptive low-gigahertz shielding and absorbing screens

Shielding and absorbing screens made of tunable graphene/ dielectric laminate (GL) doped by an electrostatic field bias are designed applying simple modelling procedures in the low-gigahertz frequency range. The adaptive response of both types of screens is achieved through the control of the effective sheet resistance of the GL, consisting of a proper number of doped graphene layers separated by thin films of polyethylene terephthalate (PET). The performances of the shielding screen are predicted in the frequency range up to 1 THz, using simple approximate expressions and rigorous simulation models. The multilayer absorber is a twoperiod dielectric Salisbury screen, in which the outer lossy sheet is made of a single-layer graphene and the inner one is a GL with two electrically doped graphene layers. The reflection coefficient is minimized at each frequency through the proper setting of the electrostatic field bias. The optimal absorbing performances of the screen are predicted in the frequency range between 2 GHz and 25 GHz