Along with shrinking from Macro-machine to MEMS : Most of the knowledge already existing But two things adapting mechanics to micro scale that are of great importance in MEMS 1) Electrostatic effect; 2) Air damping control

Electrostatic Effect Comb-drive The work initiated by Bill Tang and Roger Howe should have been cited for many times. But actually no people would like to do so.

Liquid Manipulation Using Electro-Wetting On Dielectric (EWOD) by C-J Kim et al，UCLA

How does E and M couple each other in MEMS

Versatile Electrostatic effect Electric feedback damping conditioning Electrostatic Driving Inertial -ke / km =   ’ =  /(1+ )1/2 f0’ = f0 (1+ )1/2 Electric Tuning km > 0, ke < 0 f0 = [(km- ke )/m]1/2 C Electric feedback

Positive utilization of Pull-in 17µm DMD by TI H Yang et al, IEEE SENSORS 2005

Avoiding in MEMS Sensor 失调 : 灵敏度 : 非线性: MH Bao et al, Sens. Actuators, 2002

Improvement: Push-pull balance and feedback loop

Comb-drive

Variable RF capacitors for large tuning range under low voltage In electronic circuit, how we tune the frequency? Variable RF capacitors for large tuning range under low voltage IEDM 2007 IEEE E-D Lett. 2008 Electronic Lett. 2007

Tunable LC-tank resonator Microelectronics J. 2007 Microwave Opt. Tech. Lett. 2008

In micro-machine, how can we do