Patent ID: 7777596

Claim:
A microelectromechanical resonator comprising: a resonator mass that oscillates in a bulk mode, the oscillation including a first state in which the resonator mass is contracted, at least in part, in at least one of a first direction and a second direction, and wherein in the first state, the resonator mass is expanded, at least in part, in at least one of a third direction and a fourth direction, the second direction being opposite the first direction, the fourth direction being opposite the third direction, wherein the resonator mass includes: a first plurality of regions each having a density; and a second plurality of regions each having a density, wherein the density of each of the second plurality of regions is different than the density of each of the first plurality of regions; wherein: the second plurality of regions are disposed in a non uniform arrangement; the second plurality of regions includes a first region and a second region; the resonator mass has a first major outer surface and the first region of the second plurality of regions has a first cross section parallel to the first major outer surface; the first and second regions of the second plurality of regions are spaced apart by a first distance and the first cross section has a first dimension that is at least one half the first distance; and the first dimension is greater than the first distance.