Actually I don't know the answer to you question, and I am very interested in it too. But something I'd like to add is, since you are simulating micromirrors and capacitive sensors, you might also want to take squeeze film effect into account. Especially when your device is close to the substrate (small gap distance), and operating at high frequencies. Yet as I said I am not expert, so feel free to correct me. And, if there is any news, please keep me informed too! ck ----- Original Message ----- From: "Terry Zhu"To: Sent: Sunday, April 09, 2006 8:17 PM Subject: [mems-talk] Ambient dambing effect > I am doing some simulation using ANSYS for torsional micromirror and capacitive sensors. I have seen big discrepancy in actual operation frequency/speed with the simulated ones without taking damping into account. Any one can help in how the ambient damping would be Incorporated into the simulation and what the value it should be, Or any one can provide information about this. Thanks. >