A microelectromechanical (MEMS) switch, comprising: - a substrate, - a signal supply line formed on the substrate, - a signal output line formed on the substrate, - a deformable conducting membrane connected in a conducting manner with the signal output line, said deformable conducting membrane being hung into a plane parallel to that of the substrate by anchors arranged on the substrate, said deformable conducting membrane comprising a contact plug facing the signal supply line such that, in a non-deformed state of the deformable conducting membrane, the contact plug is not in contact with the signal supply line and, in a deformed state of the deformable conducting membrane, said contact plug is in contact with the signal supply line for transmitting a signal from the signal supply line to the signal output line, - an activation electrode formed on the substrate below the deformable conducting membrane, said activation electrode being intended to deform said deformable conducting membrane for providing an electrical contact between the contact plug of the deformable conducting membrane and the signal supply line, - the deformable conducting membrane having a planar rounded shape, the anchors being arranged at its periphery so as to focus a lower stiffness in the middle region of the deformable conducting membrane, with a radial opening forming an acute angle in the direction of the signal supply line narrowing from the periphery towards the center of the deformable conducting membrane, the contact plug being formed in the middle region of the deformable conducting membrane such that the end of the signal supply line is right above the contact plug, - the activation electrode having the same shape as the deformable conducting membrane, enclosing on the substrate the end of the signal supply line, and - the gap between the lower surface of the deformable conducting membrane, facing the activation electrode, and the activation electrode being an airgap only. - a substrate, - a signal supply line formed on the substrate, - a signal output line formed on the substrate, - a deformable conducting membrane connected in a conducting manner with the signal output line, said deformable conducting membrane being hung into a plane parallel to that of the substrate by anchors arranged on the substrate, said deformable conducting membrane comprising a contact plug facing the signal supply line such that, in a non-deformed state of the deformable conducting membrane, the contact plug is not in contact with the signal supply line and, in a deformed state of the deformable conducting membrane, said contact plug is in contact with the signal supply line for transmitting a signal from the signal supply line to the signal output line, - an activation electrode formed on the substrate below the deformable conducting membrane, said activation electrode being intended to deform said deformable conducting membrane for providing an electrical contact between the contact plug of the deformable conducting membrane and the signal supply line, - the deformable conducting membrane having a planar rounded shape, the anchors being arranged at its periphery so as to focus a lower stiffness in the middle region of the deformable conducting membrane, with a radial opening forming an acute angle in the direction of the signal supply line narrowing from the periphery towards the center of the deformable conducting membrane, the contact plug being formed in the middle region of the deformable conducting membrane such that the end of the signal supply line is right above the contact plug, - the activation electrode having the same shape as the deformable conducting membrane, enclosing on the substrate the end of the signal supply line, and - the gap between the lower surface of the deformable conducting membrane, facing the activation electrode, and the activation electrode being an airgap only.