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128° YX Lithium Niobate

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Hi,

I´m interested in doing and eigenfrequency analisis of a SAW based on the model "SAW GAS SENSOR" available for COMSOL 4.1 an 3.5a. Mi interest is to obtain free velocity. If I simulate with YZ-Lithium Niobate, I get a velocity of 3425 and the reported one is 3488. This result is acceptable. But, when I try to simulate 128° YX Lithium Niobate, I shuould get a velocity of 3996 and Im not even close.

For the simulation I've used a rotated system, based on Euler Angles (0,38°,0). I've calculted the elasticity matrix, coupling matrix and permitivitty matrix taking into account the transformation available in the COMSOL userguide (Page 158). I include the matrixes obtained:

{2.02897e+011[Pa], 6.99850e+010[Pa], 1.93975e+011[Pa], 5.78425e+010[Pa], 9.03296e+010[Pa], 2.21158e+011[Pa], 1.28464e+010[Pa], 9.31243e+009[Pa], 8.00285e+009[Pa], 7.53232e+010[Pa], 0[Pa], 0[Pa], 0[Pa], 0[Pa], 5.68597e+010[Pa], 0[Pa], 0[Pa], 0[Pa], 0[Pa], -5.09155e+009[Pa], 7.79193e+010[Pa]}

{0[C/m^2], -1.88047[C/m^2], 1.71492[C/m^2], 0[C/m^2], 4.44672[C/m^2], -2.69210[C/m^2], 0[C/m^2], -1.52214[C/m^2], 2.31358[C/m^2], 0[C/m^2], 0.06738[C/m^2], 0.63381[C/m^2], 4.47243[C/m^2], 0[C/m^2], 0[C/m^2], 0.27875[C/m^2], 0[C/m^2], 0[C/m^2]}

{43.6, 0, 38.1267, 0, -7.0055, 34.63333}

My question is, do I have to include any additional consideration besides a rotated coordinate system so I can have an adequate result for this material? Does anyone know where can I get the real matrixes for this rotated material?

3 Replies Last Post 12 lug 2017, 06:34 GMT-4
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Hello Sebastian Velasquez

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Posted: 1 decade ago 9 mag 2012, 12:23 GMT-4
Hi ,
I don't know if you find the response for your question, anyway you can see this link:

www.comsol.com/community/forums/general/thread/26564/

maybe you can have some indications.
then i have the same issue with a quartz model, I used a rotation based on Euler angles (0,121.5,90), i find the matrix but i have not had the good results. So if you resolved the problem, can you tel me how you resolved it.

Thank you.

Sorry for my English.
Hi , I don't know if you find the response for your question, anyway you can see this link: http://www.comsol.com/community/forums/general/thread/26564/ maybe you can have some indications. then i have the same issue with a quartz model, I used a rotation based on Euler angles (0,121.5,90), i find the matrix but i have not had the good results. So if you resolved the problem, can you tel me how you resolved it. Thank you. Sorry for my English.

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Posted: 8 years ago 20 ago 2016, 11:55 GMT-4
Can you please help to explain why YX128 lithium niobate have Euler angles (0,38,0) ? Cause I think it should (0,-128,0) or (0, 52, 0), based on the thickness orientation in the global coordinate system. Thank you very much.
Can you please help to explain why YX128 lithium niobate have Euler angles (0,38,0) ? Cause I think it should (0,-128,0) or (0, 52, 0), based on the thickness orientation in the global coordinate system. Thank you very much.

Bilel Achour MEMS et microtechnologie

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Posted: 7 years ago 12 lug 2017, 06:34 GMT-4
Updated: 7 years ago 12 lug 2017, 07:02 GMT-4
books.google.fr/books?id=ITLn6tj4SDQC&pg=PA107&dq=128%C2%B0+YX+cut+LiNbO3+euler+angle&hl=fr&sa=X&ved=0ahUKEwi3g6eqxYPVAhVCWBoKHZtiBi0Q6AEILDAB#v=onepage&q=128%C2%B0%20YX%20cut%20LiNbO3%20euler%20angle&f=false
https://books.google.fr/books?id=ITLn6tj4SDQC&pg=PA107&dq=128%C2%B0+YX+cut+LiNbO3+euler+angle&hl=fr&sa=X&ved=0ahUKEwi3g6eqxYPVAhVCWBoKHZtiBi0Q6AEILDAB#v=onepage&q=128%C2%B0%20YX%20cut%20LiNbO3%20euler%20angle&f=false

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