MEMS resonator

A MEMS resonator comprising:

• a resonator mass in a form of a closed ring;
• a set of anchor points spaced around the ring, where the ring is connected to a fixed substrate at the anchor points by arms that extend inwardly or outwardly from the ring, wherein each of the anchor points comprises a quasi-nodal point of a minimum movement of the ring during a resonant deformation of the ring;
• a set of ring comb electrode arrangements fixed to the ring at anti-nodal points of the ring where a vibration amplitude is greatest during the resonant deformation of the ring;
• at least one drive comb electrode arrangement attached to the substrate and which interfaces with one of the set of comb electrode arrangements fixed to the ring;
• at least one sense comb electrode arrangement attached to the substrate and which interfaces with another one of the set of comb electrode arrangements fixed to the ring;
• and
• a control circuit using feedback from the sense comb electrode for controlling signals applied to the at least one drive comb electrode arrangement such that the resonator mass vibrates as a resonator in response to the signals, wherein the resonator mass, the set of ring comb electrode arrangements, the at least one drive comb electrode arrangement and at least one sense comb electrode arrangement is symmetric around the anchor points, wherein the closed ring has a rest position shape and a deformed shape, and wherein the control circuit uses the feedback to cause the resonator mass to resonantly vibrate between the rest position shape and the deformed shape in response to the signals.