A resonator array comprises substantially paralleled first and second resonant layers having resonating masses. A first set of lateral drive electrodes cause the first resonating mass to vibrate along an axis in a first geometric plane. A second set of lateral drive electrodes cause the second resonating mass to vibrate along an axis in a second geometric plane in an opposite direction of the first resonating mass by about 180 degrees. Rotation in the system causes the masses to vibrate out-of-plane in opposite directions. The opposite vibrational directions of the first and second resonating masses produces a balanced system with small motion in a bonding area between the stacked resonators. As a result, there is minimal propagation of mechanical waves from the balanced system to a substrate resulting in lower anchor loss and a high Q-factor.

A tunable Q resonator using a capacitive-piezoelectric transducer provides a flexible top electrode above an AlN resonator. The top electrode can be pulled electrostatically towards the resonator and substrate, forming a frictional contact with either the resonator or the combined resonator-electrode structure to the substrate, allowing for electrical tuning the Q of the resonator. With a sufficient electrostatic bias voltage V.sub.b, the resonator may be completely turned OFF, allowing for an integrated switchable AlN resonator. Such switchable resonator may be integrated into a radio frequency (RF) front end as a digitally selectable band pass filter element, obviating the need for ancillary micromechanical switches in the signal path. The device has been demonstrated with a Q approaching 9,000, together with ON/OFF switchability and electromechanical coupling up to 0.63%. Flexible positioning of the top electrode allows for actively controlling the series resonant frequency of the resonator through changes in capacitive coupling.

According to various embodiments, there is provided a micro-electromechanical resonator, including a substrate with a cavity therein; and a resonating structure suspended over the cavity, the resonating structure having a first end anchored to the substrate, wherein the resonating structure is configured to flex in a flexural mode along a width direction of the resonating structure, wherein the width direction is defined at least substantially perpendicular to a length direction of the resonating structure, wherein the length direction is defined from the first end to a second end of the resonating structure, wherein the second end opposes the first end.

A MEMS resonator includes a main substrate forming a receiving part at a center of the main substrate; a mass body having one end part and a center part elastically supported by both sides of the main substrate; a driving unit configured at one side of the receiving part on the main substrate and producing a driving torque by a voltage applied to both sides of the one end part of the mass body to move a position of the mass body with respect to the main substrate; and a tuning part including a pair of tuning units provided symmetrically with respect to the second elastic member, and having a beam member changing a length of the second elastic member by an actuating operation of each tuning unit to control a frequency.

Frequency stabilization is provided in a microelectromechanical systems (MEMS) oscillator via tunable internal resonance (IR). A device comprises a MEMS resonator comprising a stepped-beam structure that is a thin-layer structure. The resonator may be configured to implement IR. The stepped-beam structure may be configured to provide flexibility to adjust modal frequencies into a n:m ratio, wherein n and m are integers. The thin-layer structure provides frequency tunability by controlling the mid-plane stretching effect with an applied DC bias. The thin-layer structure compensates for a frequency mismatch from a n:m ratio due to a fabrication error. The MEMS resonator may be an oscillator.

Frequency stabilization is provided in a microelectromechanical systems (MEMS) oscillator via tunable internal resonance (IR). A device comprises a MEMS resonator comprising a stepped-beam structure that is a thin-layer structure. The resonator may be configured to implement IR. The stepped-beam structure may be configured to provide flexibility to adjust modal frequencies into a n:m ratio, wherein n and m are integers. The thin-layer structure provides frequency tunability by controlling the mid-plane stretching effect with an applied DC bias. The thin-layer structure compensates for a frequency mismatch from a n:m ratio due to a fabrication error. The MEMS resonator may be an oscillator.