Abstract: An inertial sensor comprising; a central anchor; a proof mass, wherein the proof mass surrounds the central anchor; a flexure; and a plurality of electrodes is disclosed. The flexure has a shape comprising a first plurality of spiral arms, each winding about the central anchor in a first sense, and a second plurality of spiral arms, each winding about the central anchor in a second sense, the second sense being opposite to the first sense Each of the arms are connected between the central anchor and the proof mass. Advantageously, energy lost through anchor losses and thermoelastic dissipation are reduced in this arrangement, resulting in a higher quality factor for the modes of vibration.

Abstract: There is provided an inertial sensor comprising a frame, a resonator assembly fixed to the frame comprising a first and second resonator coupled to one another by a mechanical coupling and a drive means coupled to the resonator assembly for driving the first and second resonators to vibrate. The resonator assembly is configured such that energy is transferred between the first and second resonators through the mechanical coupling. An amount of energy transferred through the mechanical coupling is dependent on the value of an input measurand acting on one of the first and second resonators. The inertial sensor also comprises a pumping means coupled to the resonator assembly for applying a pumping signal to the resonator assembly, the pumping means controlled by electrical circuitry, and a sensor assembly configured to detect the amplitude of oscillation of the first resonator at a first resonant frequency and the amplitude of oscillation of the second resonator at a second resonant frequency.