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128° YX Lithium Niobate
Posted Mar 22, 2011, 3:58 p.m. EDT MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Materials, Parameters, Variables, & Functions Version 4.1 3 Replies
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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?
Hello Sebastian Velasquez
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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.
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