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Impedance analysis - Piezo

Posted 08.01.2020, 18:53 GMT-5 Piezoelectric Devices, MEMS & Piezoelectric Devices Version 5.4 3 Replies

GA
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Hello,

I am using COMSOL 2d Axisymmetric model for the imdepance analysis.

I've used a probe defining es.nD*es.omega for the current measurement. Using point graph plotting and 1[V]/(abs(bnd1)), I am trying to create impedance plot.

For 2D model, the same procedure works with es.nD*es.omega*thickness.

But since I want model cyclindrical structure, I have to use 2d Axisymmetric model. I've attached my model. Could someone help me out with this problem.

Thank you.

Regards, GA

3 Replies Last Post 10.01.2020, 15:09 GMT-5
Dave Greve
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Posted: 5 years ago 09.01.2020, 16:25 GMT-5
Updated: 5 years ago 09.01.2020, 16:25 GMT-5

While you certainly CAN integrate the electric displacement, it is more straightforward to do a global evaluation of the terminal admittance (es.Y11). Or for impedance magnitude abs(1/es.Y11).

While you certainly CAN integrate the electric displacement, it is more straightforward to do a global evaluation of the terminal admittance (es.Y11). Or for impedance magnitude abs(1/es.Y11).
GA
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Posted: 5 years ago 10.01.2020, 04:42 GMT-5

Thank you very much for the message. Please check the attachment.

I checked with 2D model. I used both 1[V]/(abs(bnd1)) from the boundary probe (Current) and abs(1/es.Y11) as global evaluation. The one with boundary probe has Impedance of 10^4 range and for the global evaulation it is 10^2 range.

Both the impedance curve falls on the same line, but the scale is different.

Thank you very much for the message. Please check the attachment. I checked with 2D model. I used both 1[V]/(abs(bnd1)) from the boundary probe (Current) and abs(1/es.Y11) as global evaluation. The one with boundary probe has Impedance of 10^4 range and for the global evaulation it is 10^2 range. Both the impedance curve falls on the same line, but the scale is different.

Attachments:

Dave Greve
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Posted: 5 years ago 10.01.2020, 15:09 GMT-5

Well either or both are wrong. Since I don't know what or where you are probing I will put my money on es.Y11.

Since you know the permittivity of the piezo (at least approximately) a good check is verifying that the capacitance away from resonance is correct.

Well either or both are wrong. Since I don't know what or where you are probing I will put my money on es.Y11. Since you know the permittivity of the piezo (at least approximately) a good check is verifying that the capacitance away from resonance is correct.

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