A micro-electro-mechanical variable capacitor has a first and a second electrode, and a dielectric region arranged on the first electrode. An intermediate electrode is arranged on the dielectric region. The first electrode is fixed and anchored to a substrate, and the second electrode includes a membrane movable with respect to the first electrode according to an external actuation, in particular an electrostatic force due to an actuation voltage applied between an actuation electrode and the first electrode. The second electrode is suspended over the intermediate electrode in a first operating condition, and contacts the intermediate electrode in a second operating condition; in particular, in the second operating condition, a short-circuit is established between the second electrode and the intermediate electrode.