According to one aspect of the invention, there is proposed a capacitive radiofrequency MicroElectroMechanical System or capacitive RF MEMS comprising a metallic membrane suspended above an RF transmission line and resting on ground planes, and exhibiting a lower face, an upper face opposite to the lower face and a first layer comprising a refractory metallic material at least partially covering the upper face of the membrane so as to prevent the heating of the membrane.