Patent ID: 8222974

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; 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; 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; each of the second plurality of regions has a length and a width, the length being longer than the width; the second plurality of regions includes a first region and a second region; and 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.