Hello

there are manly three storages for energy in an electrostatically actuated cantilever MEMS system: a) the electrostatic energy of the cantilever capacitance b) the potential energy of the cantilever sprig (deflection) c) the kinetic energy of the moving cantilever mass. Most probably the energy losses are quite low if you swith of the electrostatic actuator part. You must provide an energy drain (e.g. a resistor connected to the cantilever actuator capacity) to enable the system to get rid of the energy.

sample literature: patent application US2009309521A1

Inventors KIMBALL ROBERT ALLEN [US]; YEE HAROLD GEE [US]

down load it from the european patent office

https://www.epo.org/searching-for-patents/technical/espacenet.html

open espacenet

use US2009309521A1 in smart search

select the relevant invention "driver for MEMS device"

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The resistor 32 is used for damping.

Bernd

beside of the Things mentioned in MEMS structures one should also consider air damping from the close by housing and ground plate.

The MEMS cantilever is usually modelled as a spring with damping. Generally, if one releases a spring, it needs a certain time period to reach the settled position. Further, your cantilever has an electromechanical coupling that causes the mechanical vibration is "transferred" into the electrical vibration (oscillation). You can see that oscillation.

Please also look up MEMS realisations of "Reed frequency meters".

How does it work? MEMS cantilever of different length reach resonance at their different natural frequencies.

The oscillatory response only can be seen when you have under damped scenario...you can estimate the squeeze film damping by using any damping solver simulator... alternatively you can also calculate it... The squeeze film damping varies linearly with square of the area, and inversely proportional to (gap)^3...thereafter divide it with the critical damping by the formula 2m×wn......If the ratio more than 1 it's overdamped ... you will not see and oscillatory response...if it's less than 1 then oscillatory response will be seen