The present disclosure provides an aerosol sensing method. The aerosol sensing method includes steps of providing an entering process, providing a particle collecting process and providing a measuring process. The entering process is to allow an aerosol to enter a chamber of a thermal-piezoresistive oscillator-based aerosol sensor, and a thermal-piezoresistive resonator is disposed in the chamber. The particle collecting process is to allow particulate matters in the aerosol to land on at least one proof-mass of the thermal-piezoresistive resonator when the thermal-piezoresistive resonator is not driven. The measuring process is to use an electrical signal to drive the thermal-piezoresistive resonator and measure a resonant frequency of the thermal-piezoresistive resonator. The particle collecting process and the measuring process are operated in a repetitive cycle for measuring changes of the resonant frequency of the thermal-piezoresistive resonator to measure the particulate matters of the aerosol.

The present disclosure provides an aerosol sensing method. The aerosol sensing method includes steps of providing an entering process, providing a particle collecting process and providing a measuring process. The entering process is to allow an aerosol to enter a chamber of a thermal-piezoresistive oscillator-based aerosol sensor, and a thermal-piezoresistive resonator is disposed in the chamber. The particle collecting process is to allow particulate matters in the aerosol to land on at least one proof-mass of the thermal-piezoresistive resonator when the thermal-piezoresistive resonator is not driven. The measuring process is to use an electrical signal to drive the thermal-piezoresistive resonator and measure a resonant frequency of the thermal-piezoresistive resonator. The particle collecting process and the measuring process are operated in a repetitive cycle for measuring changes of the resonant frequency of the thermal-piezoresistive resonator to measure the particulate matters of the aerosol.

The present disclosure describes a micromechanical resonator comprising a resonator element (40) having a length (l.sub.1) and a width (w.sub.1) that is perpendicular to the length. The resonator element has a length-to-width aspect ratio in a range of 1.8 to 2.2. The resonator element is suspended to a support structure with two or more anchors (41, 43). Each of the two or more anchors is attached to a first location or a second location. The first location is at a shorter side (42) of the resonator element. The first location divides the width (w.sub.1) of the resonator element into a larger portion (w.sub.3) and a smaller portion (w.sub.2) such that a ratio between said smaller portion (w.sub.2) and the whole width (w.sub.1) is in a range of 0.10 to 0.28. The second location is at a longer side (44). The second location divides the length (l.sub.1) of the resonator element into a larger portion (l.sub.3) and a smaller portion (l.sub.2) such that a ratio between said smaller portion (l.sub.2) and the whole length (l.sub.1) is in a range of 0.36 to 0.48.

Reference oscillators are ubiquitous in timing applications generally, and in modern wireless communication devices particularly. Microelectromechanical system (MEMS) resonators are of particular interest due to their small size and potential for integration with other MEMS devices and electrical circuits on the same chip. In order to support their use in high volume low cost applications it would be beneficial for MEMS designers to have MEMS resonator designs and manufacturing processes that whilst employing low cost low resolution semiconductor processing yield improved resonator performance thereby reducing the requirements of the oscillator circuitry. It would be further beneficial for the oscillator circuitry to be able to leverage the improved noise performance of differential TIAs without sacrificing power consumption.

A vibration device that includes a vibration portion, a support portion connected to the vibration portion, a bending-vibrating portion connected to the support portion, and a frame-shaped base portion connected to the bending-vibration portion and disposed so as to surround the vibration portion. The base portion defines a slit that extends in a first direction crossing a second direction in which the support portion extends from the vibration portion, the slit defining first and second fixed ends of the bending-vibrating portion and which are continuous with the base portion. A length between a portion of the bending-vibrating portion connected to the support portion to one of the first and second fixed ends of the bending-vibrating portion is in a range of /8 to 3/8, where denotes a wavelength of a bending vibration corresponding to a frequency of a characteristic vibration of the vibration portion.

A vibrator that includes a silicon substrate, an electrode facing a surface of the silicon substrate, and a piezoelectric body between the silicon substrate and the electrode and that produces contour vibration in a plane along the surface of the silicon substrate in accordance with a voltage applied to the electrode. The vibrator includes one or more substantially rectangular vibration regions each having a long side parallel to a node of the contour vibration of the piezoelectric body and a short side orthogonal to the node of the contour vibration of the piezoelectric body and corresponding to a half-wavelength of the contour vibration. The resonator satisfies W/T4 and y=0.85(1/T)+0.570.05 where T is the thickness of the silicon substrate, W is the width of the short side of the vibration region, and y is the resistivity of the silicon substrate.

A resonator that includes a piezoelectric vibrator, a frame, and a first node generator between the piezoelectric vibrator and the frame. Moreover, a first connecting arm connects the first node generator to the piezoelectric vibrator that opposes the first, and a first holding arm connects the first node generator to a part of the frame that opposes the first node generator. The first node generator includes a width extending in a second direction, which is orthogonal to a first direction of the first connecting arm, that is a maximum width where the first node generator is closer to the first connecting arm than a center of the first node generator relative to the first direction. Moreover, the width of the first node generator gradually decreases from the maximum width as the first node generator extends towards the first holding arm.

A MEMS (microelectromechanical system) resonator assembly (100), comprising a support structure (102), a resonator element (101) suspended to the support structure (102), and an actuator for exciting the resonator element (101) to a resonance mode. The resonator element (101) vibrates at resonance frequency f.sub.0 and comprises at least one bulk acoustic resonator (110a, 110b). The ESR*A*f.sub.0 values of the resonator assembly (100) are in the range from 12 mm.sup.2 MHz to 83 mm.sup.2 MHZ.

A MEMS (microelectromechanical system) resonator assembly (100), comprising a support structure (102), a resonator element (101) suspended to the support structure (102), and an actuator for exciting the resonator element (101) to a resonance mode. The resonator element (101) comprises two bulk acoustic resonators (110a, 110b) and a flexural mode resonator (120). The flexural mode resonator (120) mechanically connects the two bulk acoustic resonators (110a, 110b), and the MEMS resonator assembly (100) is configured to vibrate in a collective resonance mode in which motions of the two bulk acoustic resonators (110a, 110b) are substantially in the same or 180 degrees shifted phase with respect to each other.

A microelectromechanical system (MEMS) device includes a temperature compensating structure including a first beam suspended from a substrate and a second beam suspended from the substrate. The first beam is formed from a first material having a first Young's modulus temperature coefficient. The second beam is formed from a second material having a second Young's modulus temperature coefficient. The body may include a routing spring suspended from the substrate. The routing spring may be coupled to the first beam and the second beam. The routing spring may be formed from the second material. The first beam and the second beam may have lower spring compliance than the routing spring. The MEMS device may be a resonator and the temperature compensating structure may have dimensions and a location such that the temperature compensation structure modifies a temperature coefficient of frequency of the resonator independent of a mode shape of the resonator.