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Comb drive resonator in COMSOL

Posted 22 apr 2013, 19:27 GMT-4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices Version 4.3a 4 Replies

Ngoc Nguyen
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Hi,

I need to use COMSOL to simulate a comb drive as a resonator. I used poly-Si for the comb drive and covered it by air. I assume that I need to choose Electromechanics Physics for my model. It means that I have to apply a voltage for the comb drive and investigate the eigenfrequency, which is also the resonant frequency.
However, I got 2 problems:
1. After applying bias voltage for the comb drive, I cannot choose the boundaries to fix. It says that the boundaries I chose are not applicable.
2. When I try to compute, there has been an error saying that the mass matrix is zero. I think this may be because of the boundary problem above.
How can I fix my problem? I attach my model here for the convenience.
I am a newbie in COMSOL and I appreciate any help.
Thank you in advance.

Attachments:

4 Replies Last Post 7 apr 2016, 17:17 GMT-4
Bertil Nistad COMSOL Employee

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Posted: 1 decade ago 25 apr 2013, 07:15 GMT-4
Hi,
It appears that you have not selected the correct parts of the model to be linear elastic dielectric.
Have a look at the biased resonator model in the model library, and select the parts that are linear elastic.

I'm pretty confident that you will make it work!

Best regards
Bertil
Hi, It appears that you have not selected the correct parts of the model to be linear elastic dielectric. Have a look at the biased resonator model in the model library, and select the parts that are linear elastic. I'm pretty confident that you will make it work! Best regards Bertil
Ngoc Nguyen
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Posted: 1 decade ago 26 apr 2013, 07:00 GMT-4
Hi,

Thank you very much for your recommendation. I chose the linear elastic material for my model and it worked. Now I could choose the boundaries I want to fix. One more thing, it seems that I applied too high biased voltage for the drive, but after modifying this value (5V), the model worked quite well.

Regards,
Ngoc
Hi, Thank you very much for your recommendation. I chose the linear elastic material for my model and it worked. Now I could choose the boundaries I want to fix. One more thing, it seems that I applied too high biased voltage for the drive, but after modifying this value (5V), the model worked quite well. Regards, Ngoc
Li Chenchen
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Posted: 1 decade ago 18 ott 2013, 03:59 GMT-4
hi,Ngoc Nguyen
i want to calculate the resonator's damping ,do you konw how to calculate?can you share your mode with me ,i am also a newbie ,thank you
hi,Ngoc Nguyen i want to calculate the resonator's damping ,do you konw how to calculate?can you share your mode with me ,i am also a newbie ,thank you
Bhavana Govindareddigari
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Posted: 8 years ago 7 apr 2016, 17:17 GMT-4
Hi, i am unable to open the file.please help me to open the comb resonator.mph file.

Thanks
G.Bhavana
Hi, i am unable to open the file.please help me to open the comb resonator.mph file. Thanks G.Bhavana

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