Microelectromechanical (MEMS) devices are finding increasing utility in applications driven by requirements for miniaturization portability light weight low cost and low power consumption. A rapidly growing market for such devices is in sensing applications such as motion and acceleration sensing. Conventional MEMS accelerometers and inertial sensors are based on deflection of a structure such as a proof mass that is mechanically coupled to the rest of the device. However mechanical coupling can introduce short-circuiting and mechanical parasitic effects including thermal loss noise structural energy loss and concerns about fatigue life cycle limits and strain limits. Researchers at the University of California Berkeley have developed a MEMS device in which the proof mass is mechanically isolated from other parts of the device by electrostatic repulsion. Decoupling the proof mass eliminates the inherent weaknesses (short-circuiting parasitic effects etc.) of mechanically coupled devices. The improved Berkeley devices are largely insensitive to operating temperatures and depending on the leakage currents and environmental conditions require almost no additional power after charging. Sample applications include charge storage devices GHz resonators and motion and acceleration sensors.
1) No mechanical wear fatigue or short-circuiting 2) Reduced electric and mechanical parasitics such as electronic noise and thermal conduction. 3) Large operating range of temperatures and accelerations