Mr Yan Xin,

  I will try to answer your questions.

  1 the damping of the system composed of  viscous
 damping,thermoelastic damping and anchor losses,
 but shall  i need  consider all the damping for the
 damping coefficient in the motion equations or  just
consider the viscous damping only?

--Consider all mechanisms. But if you don't adopt
vacuum packaging, the viscous damping will dominate.

 2 how to calculate or deduce the viscous
 damping(couette damping,squeeze
 damping) of the device under the different pressure?

--A lot of papers deal with that problem. Some
examples are:

Slide damping: Timo Veijola, et al, Compact damping
models for laterally moving microstructures with gas
rarefaction effects, JMEMS vol.10, No.2, 2001.

Squeeze damping: Minhang Bao, et al, Squeeze film air
damping in MEMS, Sensors and actuators A 136(2007)
3-27.



 3  Does anyone knows a good paper to discuss the
 deduction of the viscous damping?

--- Refer to the answer above.

--- Yan Xin wrote:

> Hi everyone,
>
> i meet a damping calculation problem when i design a
> microgyroscope,  i
> found several damping models in some thesises, but i
> got many exactly
> different results with their equations in the same
> condition. It's my first
> time to design the inertial sensor and with no
> experience in the clean room,
> so i have no idea how different the device
> performance will be by
> this exactly different results.
>
> My questions are :
>
> 1 the damping of the system composed of  viscous
> damping,thermoelastic damping and anchor losses,
> but shall  i need  consider all the damping for the
> damping coefficient in
> the motion equations or  just consider the viscous
> damping only?
>
> 2 how to calculate or deduce the viscous
> damping(couette damping,squeeze
> damping) of the device under the different pressure?
>
> 3  Does anyone knows a good paper to discuss the
> deduction of the viscous
> damping?
>
> Thank you for suggestion,
>
> Sincerely yours,
>
> XinYan