Time base comprising an integrated micromechanical ring resonator

A time base comprising a resonator and an integrated electronic circuit for driving said resonator into oscillation and for producing, in response to said oscillation, a signal having a determined frequency, wherein said resonator is an integrated micromechanical ring resonator supported above a substrate and adapted to oscillate, according to a first oscillation mode, around an axis of rotation substantially perpendicular to said substrate, said ring resonator comprising:

• a central post extending from said substrate along said axis of rotation;
• a free-standing oscillating structure connected to said central post and including:
• an outer ring coaxial with said axis of rotation and
• a plurality of spring elements disposed symmetrically around said central post and connecting said outer ring to said central post;
• and
• at least one pair of diametrically opposed electrode structures disposed around said outer ring and connected to said integrated electronic circuit,
• and wherein said spring elements have a curved shape and are connected substantially perpendicularly to said central post by first junctions, each of said spring elements extending away from said central post in the prolongation of a radial line crossing said axis of rotation.