Electromechanical variable-capacitance capacitor with four electrodes

A variable-capacitance capacitor having first and second electrodes mobile with respect to each other, separated by an insulating region, and third and fourth electrodes electrically insulated from the first and second electrodes, capable of receiving a control signal to vary the relative position of the first and second electrodes in order to vary the capacitance between the first and second electrodes,

• wherein:
• the first electrode comprises first and second conductive parts fixed with respect to each other and electrically connected to each other;
• the second electrode comprises a third conductive part mobile with respect to the first and second conductive parts, the position of the third conductive part with respect to the first and second conductive parts being a function of the control signal applied between the third and fourth electrodes;
• and
• there exists at least one position of the third conductive part with respect to the first and second conductive parts for which, whatever the voltage applied between the first and second electrodes, the electrostatic force exerted on the third conductive part by the first conductive part compensates for the electrostatic force exerted on the third conductive part by the second conductive part.