Abstract: A micro-electromechanical resonator suspended from an anchor. The resonator has: a length; a first width at a first distance from the anchor; and a second width at a second, greater distance from the anchor. The second width is greater than the first width, and the width of the resonator tapers gradually along at least part of its length from the second width to the first width.

Abstract: A resonator comprising a beam formed from a first material having a first Young's modulus and a first temperature coefficient of the first Young's modulus, and a second material having a second Young's modulus and a second temperature coefficient of the second Young's modulus, a sign of the second temperature coefficient being opposite to a sign of the first temperature coefficient at least within operating conditions of the resonator, wherein the ratio of the cross sectional area of the first material to the cross sectional area of the second material varies along the length of the beam, the cross sectional areas being measured substantially perpendicularly to the beam.

Abstract: A resonator in which in addition to the normal anchor at a nodal point, a second anchor arrangement is provided and an associated connecting arm between the resonator body and the second anchor arrangement. The connecting arm connects to the resonator body at a non-nodal point so that it is not connected to a normal position where fixed connections are made. The connecting arm is used to suppress transverse modes of vibration.

Abstract: A resonator comprising a resonator body and actuation electrodes for driving the resonator into a resonant mode, in which the resonator body vibrates parallel to a first axis. The resonator comprises means to apply a voltage to the resonator in a direction perpendicular to the first axis direction. This serves to shift the frequency of resonant modes other than the principal resonant mode, and this allows increased amplitude of output signal from the resonator.

Abstract: A bulk-acoustic-mode MEMS resonator has a first portion with a first physical layout, and a layout modification feature. The resonant frequency is a function of the physical layout, which is designed such that the frequency variation is less than 150 ppm for a variation in edge position of the resonator shape edges of 50 nm. This design combines at least two different layout features in such a way that small edge position variations (resulting from uncontrollable process variation) have negligible effect on the resonant frequency.

Abstract: A microphone has a membrane (20) mounted to vibrate in response to pressure fluctuations, a backplate (30) facing the membrane and being more rigid than the membrane, and circuitry (95) for sensing the vibrations relative to the backplate, the backplate being prestressed and having a geometry such that a response of the backplate to structure borne vibration matches a corresponding response of the membrane. This can help reduce or minimize relative movement between these surfaces caused by structure borne vibration and hence improve the signal-to-noise ratio of the microphone. The geometry can be a hub and spoke arrangement.

Abstract: A microphone comprises a substrate (20), a microphone membrane (10) defining an acoustic input surface and a backplate (11) supported with respect to the membrane with a fixed spacing between the backplate (11) and the membrane (10). A microphone periphery area comprises parallel corrugations (24) in the membrane (10) and backplate (11). By using the same corrugated suspension for both the membrane and the backplate, the sensitivity to body noise is optimally suppressed.

Abstract: A micro-electromechanical resonator suspended from an anchor. The resonator has: a length; a first width at a first distance from the anchor; and a second width at a second, greater distance from the anchor. The second width is greater than the first width, and the width of the resonator tapers gradually along at least part of its length from the second width to the first width.

Abstract: A MEMS piezoresistive resonator (8, 78) is driven at a higher order eigenmode (32) than the fundamental eigenmode (31). The route of flow of a sense current (22) is arranged in relation to a characteristic of the higher order eigenmode (32), for example by being at a point of maximum displacement (50) or at a point of maximum rate of change with respect to distance (x) of displacement of the higher order eigenmode (32). The route of flow of the sense current (22) may be arranged by fabricating the MEMS piezoresistive resonator (8, 78) with a trench (15) formed between two beams (11, 12) of the MEMS piezoresistive resonator (8, 78), the end of the trench being located at the above mentioned position.

Abstract: A resonator comprising a beam formed from a first material having a first Young's modulus and a first temperature coefficient of the first Young's modulus, and a second material having a second Young's modulus and a second temperature coefficient of the second Young's modulus, a sign of the second temperature coefficient being opposite to a sign of the first temperature coefficient at least within operating conditions of the resonator, wherein the ratio of the cross sectional area of the first material to the cross sectional area of the second material varies along the length of the beam, the cross sectional areas being measured substantially perpendicularly to the beam.

Abstract: A MEMS piezoresistive resonator (8, 78) is driven at a higher order eigenmode (32) than the fundamental eigenmode (31). The route of flow of a sense current (22) is arranged in relation to a characteristic of the higher order eigenmode (32), for example by being at a point of maximum displacement (50) or at a point of maximum rate of change with respect to distance (x) of displacement of the higher order eigenmode (32). The route of flow of the sense current (22) may be arranged by fabricating the MEMS piezoresistive resonator (8, 78) with a trench (15) formed between two beams (11, 12) of the MEMS piezoresistive resonator (8, 78), the end of the trench being located at the above mentioned position.