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saw sensor for pressure measurement

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hello,
i am designing a saw sensor for pressure measurement.can somebody suggest me which formula i need to use in comsol in order to measure pressure. it should be related to change in frequency of saw sensor by application of pressure.

33 Replies Last Post Oct 29, 2013, 7:18 a.m. EDT

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Posted: 1 decade ago Mar 1, 2012, 9:17 a.m. EST
Hi,

I don't think anybody can suggest a formula. The procedure will be:

1. Set up your model with proper electrical and mechanical boundary conditions
2. Apply pressure to the appropriate boundary
3. Determine the electrical frequency response of the system.
Put all this into a parametric study using pressure as the parameter.

This will give you the pressure-frequency relationship and you might try to fit this to an appropriate test function to obtain a formula. What the test function could look like depends on your SAW design.

Cheers
Edgar
Hi, I don't think anybody can suggest a formula. The procedure will be: 1. Set up your model with proper electrical and mechanical boundary conditions 2. Apply pressure to the appropriate boundary 3. Determine the electrical frequency response of the system. Put all this into a parametric study using pressure as the parameter. This will give you the pressure-frequency relationship and you might try to fit this to an appropriate test function to obtain a formula. What the test function could look like depends on your SAW design. Cheers Edgar

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Posted: 1 decade ago Mar 17, 2012, 1:31 a.m. EDT
Hello Mr.Edgar,
Thank you for your reply. I have designed the idt structure and given the boundary conditions also both mechanical and electrical.I am new to this comsol software so dont know much about it. Should i send you my model .If u review it and help me finding suitable solution i will be grateful to you sir.
Looking forward to your reply.
Regards
Rohan kumar
Hello Mr.Edgar, Thank you for your reply. I have designed the idt structure and given the boundary conditions also both mechanical and electrical.I am new to this comsol software so dont know much about it. Should i send you my model .If u review it and help me finding suitable solution i will be grateful to you sir. Looking forward to your reply. Regards Rohan kumar

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Posted: 1 decade ago Mar 17, 2012, 3:52 a.m. EDT
hi Rohan !
Can you attach your file?
hi Rohan ! Can you attach your file?

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Posted: 1 decade ago Mar 22, 2012, 1:55 a.m. EDT
i heve posted my two designs that i am tring to implement
i heve posted my two designs that i am tring to implement


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Posted: 1 decade ago Mar 29, 2012, 3:32 a.m. EDT
Dear Rohan !
How is your work ? i am also designing a saw sensor for pressure measurement. I have post some picture which I got.
I think we can exchange more.
Dear Rohan ! How is your work ? i am also designing a saw sensor for pressure measurement. I have post some picture which I got. I think we can exchange more.


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Posted: 1 decade ago Mar 30, 2012, 3:38 a.m. EDT
Hello Nguyên Vinh,
Thank you for your reply.yes we can exchange information about the design. So which version of COMSOL you are using ?What is the range of your pressure measurement ?
Hello Nguyên Vinh, Thank you for your reply.yes we can exchange information about the design. So which version of COMSOL you are using ?What is the range of your pressure measurement ?

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Posted: 1 decade ago Mar 30, 2012, 1:42 p.m. EDT
Hi Rohan !
Thanks for your enthusiasm. I use version 4.2, which i put pressure on the surface is 10kpa. i think i have simulated fairly accurately, but I do not understand why the input and output frequency does not change. Do you have trouble like me ?
Hi Rohan ! Thanks for your enthusiasm. I use version 4.2, which i put pressure on the surface is 10kpa. i think i have simulated fairly accurately, but I do not understand why the input and output frequency does not change. Do you have trouble like me ?

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Posted: 1 decade ago Mar 31, 2012, 2:29 p.m. EDT
Hello Nguyên Vinh,
Thank you for your reply. Can you send me your simulation i will check it. There must be change in frequency. Let me check it if you don't have any problem.Waiting for your reply.

Regards

Rohan Kumar
Hello Nguyên Vinh, Thank you for your reply. Can you send me your simulation i will check it. There must be change in frequency. Let me check it if you don't have any problem.Waiting for your reply. Regards Rohan Kumar

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Posted: 1 decade ago Apr 1, 2012, 4:08 a.m. EDT
Dear Rohan Kumar !
I'm glad because of your suggestion. Yes, this is my file. I have difficulty in placing pressure on the boundary condition to see the change of frequency that I put in.
Expecting your answer.

Nguyên Vinh
Dear Rohan Kumar ! I'm glad because of your suggestion. Yes, this is my file. I have difficulty in placing pressure on the boundary condition to see the change of frequency that I put in. Expecting your answer. Nguyên Vinh


Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 1, 2012, 5:47 p.m. EDT
Hi!

I am also designing a SAW pressure Sensor.

I read that you are designing a SAW sensor, so it would be great that we could work together. Right now I am simulating a single cell of the IDT. I am working with 128 YX LiNBO3. I got the expect results, and now I am trying to simulate a ten electrodes IDT, but I have some issues with the PML boundaries.

Waiting for your answer

Regards,
Hi! I am also designing a SAW pressure Sensor. I read that you are designing a SAW sensor, so it would be great that we could work together. Right now I am simulating a single cell of the IDT. I am working with 128 YX LiNBO3. I got the expect results, and now I am trying to simulate a ten electrodes IDT, but I have some issues with the PML boundaries. Waiting for your answer Regards,

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Posted: 1 decade ago Apr 2, 2012, 12:15 a.m. EDT
Hi !
I also think it's a great idea for all of us. Yes, I am willing to exchange about this design. Can you post your file?. I do not know the domain that you analyze , because I think each region will have different boundary conditions. if you analyze the Eigenfrequency domain, I think I have a simulation that you can refer.
Andrés Guillermo Borrero, can you solve my problems ? I have difficulty in placing pressure on the boundary condition to see the change of frequency that I put in.
I'm very grateful if someone could help me ?
Expecting to soon get an answer.

Regards

Nguyên Vinh
Hi ! I also think it's a great idea for all of us. Yes, I am willing to exchange about this design. Can you post your file?. I do not know the domain that you analyze , because I think each region will have different boundary conditions. if you analyze the Eigenfrequency domain, I think I have a simulation that you can refer. Andrés Guillermo Borrero, can you solve my problems ? I have difficulty in placing pressure on the boundary condition to see the change of frequency that I put in. I'm very grateful if someone could help me ? Expecting to soon get an answer. Regards Nguyên Vinh


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Posted: 1 decade ago Apr 2, 2012, 3:32 a.m. EDT
HI Nguyên Vinh,
YOU SHOULD DESIGN THE SNGLE IDT STRUCTURE FIRST LIKE Andrés Guillermo Borrero. which papers you are following can you send them
HI Nguyên Vinh, YOU SHOULD DESIGN THE SNGLE IDT STRUCTURE FIRST LIKE Andrés Guillermo Borrero. which papers you are following can you send them

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Posted: 1 decade ago Apr 2, 2012, 3:38 a.m. EDT
HI Nguyên Vinh,
YOU SHOULD DESIGN THE SNGLE IDT STRUCTURE FIRST LIKE Andrés Guillermo Borrero. which papers you are following can you send them
HI Nguyên Vinh, YOU SHOULD DESIGN THE SNGLE IDT STRUCTURE FIRST LIKE Andrés Guillermo Borrero. which papers you are following can you send them

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Posted: 1 decade ago Apr 2, 2012, 4:18 a.m. EDT
Hi Rohan Kumar !
I also design original the single IDT structure first, I find the appropriate frequencies. I then analyzed in the time domain, I want to see the movement of the saw depends on time. I've put a sine wave on the electrodes of IDT. and I've seen results. however, now I want to put pressure on the surface of the sensor, and check the frequency that I applied to the sine wave equation has changed or not., my work did not as expected.
Rohan Kumar,How did you simulate on this change . is it like me ?
Hi Rohan Kumar ! I also design original the single IDT structure first, I find the appropriate frequencies. I then analyzed in the time domain, I want to see the movement of the saw depends on time. I've put a sine wave on the electrodes of IDT. and I've seen results. however, now I want to put pressure on the surface of the sensor, and check the frequency that I applied to the sine wave equation has changed or not., my work did not as expected. Rohan Kumar,How did you simulate on this change . is it like me ?

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Posted: 1 decade ago Apr 2, 2012, 4:29 a.m. EDT
Hi Nguyên Vinh,
yes i simulated the single idt .it is working . i did the frequency analysis of the structure . i found the resonant frequency of the idt 1st then applied the pressure to it . there was a frequency shift because of that.
Hi Nguyên Vinh, yes i simulated the single idt .it is working . i did the frequency analysis of the structure . i found the resonant frequency of the idt 1st then applied the pressure to it . there was a frequency shift because of that.

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Posted: 1 decade ago Apr 2, 2012, 4:41 a.m. EDT
Hi Rohan Kumar !
I simulated also like you. I have seen the frequency change. you do not work in the time domain analysis. in fact, we must apply the sine wave signal and determines the pressure through the change of output frequency.

Hi Rohan Kumar ! I simulated also like you. I have seen the frequency change. you do not work in the time domain analysis. in fact, we must apply the sine wave signal and determines the pressure through the change of output frequency.

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Posted: 1 decade ago Apr 2, 2012, 4:47 a.m. EDT
Nguyên Vinh
yes you are right. can you send the single idt structure.we have to do like this.
Nguyên Vinh yes you are right. can you send the single idt structure.we have to do like this.

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Posted: 1 decade ago Apr 2, 2012, 4:49 a.m. EDT
Hi Rohan Kumar !
Because of the large file size, I can not post up. I take a page so we can see that
Hi Rohan Kumar ! Because of the large file size, I can not post up. I take a page so we can see that

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Posted: 1 decade ago Apr 2, 2012, 4:54 a.m. EDT
hi Nguyên Vinh,
delete the study part from simulation and send it . or zip it and send it to my email id rohankumar03@gmail.com as i dont have office file in my i system
hi Nguyên Vinh, delete the study part from simulation and send it . or zip it and send it to my email id rohankumar03@gmail.com as i dont have office file in my i system

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Posted: 1 decade ago Apr 2, 2012, 5:05 a.m. EDT
Hi Rohan Kumar !
I just created file as I did before. it is based on modules of COMSOL library. you can change the pressure (large enough) to see the frequency change
Hi Rohan Kumar ! I just created file as I did before. it is based on modules of COMSOL library. you can change the pressure (large enough) to see the frequency change


Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 2, 2012, 9:24 a.m. EDT
Hi!,

Here are my files. IDT Celda Unitaria is a single IDT, I have performed a frequency analysis to see the admitance. I Also attached this graphic (Admitancia IDT celda con 60 Lambda) . Prueba SAW IDT is a 10 electrodes IDT, with this I have a problem with PML boundaries that I used to avoid the reflections on the material frontiers (The error i get from comsol is "Comsol could not find any spherical or cylindrical regions."). Al so I Attached the results about admitance (Admitancia IDT 10 Electrodos ...).

Please, let me know if you can resolve the problems with PML. I am using COMSOL 4.2a

I have not performed any simulations with pressure yet. How do you simulate the diaphragm bending??

Waiting for your reply.

Regards.

Guillermo Borrero
Hi!, Here are my files. IDT Celda Unitaria is a single IDT, I have performed a frequency analysis to see the admitance. I Also attached this graphic (Admitancia IDT celda con 60 Lambda) . Prueba SAW IDT is a 10 electrodes IDT, with this I have a problem with PML boundaries that I used to avoid the reflections on the material frontiers (The error i get from comsol is "Comsol could not find any spherical or cylindrical regions."). Al so I Attached the results about admitance (Admitancia IDT 10 Electrodos ...). Please, let me know if you can resolve the problems with PML. I am using COMSOL 4.2a I have not performed any simulations with pressure yet. How do you simulate the diaphragm bending?? Waiting for your reply. Regards. Guillermo Borrero


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Posted: 1 decade ago Apr 2, 2012, 11:38 p.m. EDT
Hi Guillermo Borrero !
it is a pity, I can not open your file. I used version 4.2.Can you capture images of what you did and send it to me ?

Regards.
Nguyên Vinh
Hi Guillermo Borrero ! it is a pity, I can not open your file. I used version 4.2.Can you capture images of what you did and send it to me ? Regards. Nguyên Vinh

Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 3, 2012, 1:24 a.m. EDT
Hi!

Sure I can send you the images. I try to put all necessary to understand what I do for each case. Let me know any doubt. In the ten electrodes IDT the PML regions do not work properly, they seems to be disconected of the entire system.

Let me know if you have any suggestion or comment.

Waiting your reply.

Regards

Guillermo Borrero
Hi! Sure I can send you the images. I try to put all necessary to understand what I do for each case. Let me know any doubt. In the ten electrodes IDT the PML regions do not work properly, they seems to be disconected of the entire system. Let me know if you have any suggestion or comment. Waiting your reply. Regards Guillermo Borrero


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Posted: 1 decade ago Apr 3, 2012, 2:35 a.m. EDT
Hi Guillermo Borrero !

I think that they seems to be disconected of the entire system is correct. My opinion, PML is a piezoelectric material, and what you simulate is for PML. the remaining components are not related to PML. I do not know how you put the fixed conditions for the model. Let me know this.

Guillermo Borrero,Can you tell me how you simulate the pressure conditions in your model ?

Regards

Nguyên Vinh
Hi Guillermo Borrero ! I think that they seems to be disconected of the entire system is correct. My opinion, PML is a piezoelectric material, and what you simulate is for PML. the remaining components are not related to PML. I do not know how you put the fixed conditions for the model. Let me know this. Guillermo Borrero,Can you tell me how you simulate the pressure conditions in your model ? Regards Nguyên Vinh

Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 3, 2012, 2:48 a.m. EDT
Hi!

I do not understand when you say that PML is a piezoelectric material. PML is a kind of boundary to avoid the reflections on the material frontiers.

What fixed conditions specifically do you refer ?

Currently I am not simulating pressure conditions, before I want to create the correct model of the IDT and next I will add the reflectors and I think I should put all in a kind of diaphragm, so with the pressure to generate a bending of it. And a change in propagation velocity and delay time.

Let me know what is your plan?

waiting for your answer and comments.

Regards.

PS : do you have facebook or anything so we can chat?

Hi! I do not understand when you say that PML is a piezoelectric material. PML is a kind of boundary to avoid the reflections on the material frontiers. What fixed conditions specifically do you refer ? Currently I am not simulating pressure conditions, before I want to create the correct model of the IDT and next I will add the reflectors and I think I should put all in a kind of diaphragm, so with the pressure to generate a bending of it. And a change in propagation velocity and delay time. Let me know what is your plan? waiting for your answer and comments. Regards. PS : do you have facebook or anything so we can chat?

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Posted: 1 decade ago Apr 3, 2012, 3:25 a.m. EDT
Hi Guillermo Borrero !

I'm sorry I was a bit busy now.

My plan is I will put a sine wave on the electrodes, and I applied pressure to the surface. I want to see the change in frequency of the system. But that can not,I do not know what i have do now

www.comsol.com/community/forums/general/thread/14491/ . I think the information here will be useful for your simulation.

Regards

Nguyên Vinh
Hi Guillermo Borrero ! I'm sorry I was a bit busy now. My plan is I will put a sine wave on the electrodes, and I applied pressure to the surface. I want to see the change in frequency of the system. But that can not,I do not know what i have do now http://www.comsol.com/community/forums/general/thread/14491/ . I think the information here will be useful for your simulation. Regards Nguyên Vinh

Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 3, 2012, 10:42 a.m. EDT
Hi!

Thanks, I already had seen that forum, but I was not able to fix my errors. Are you designing a delay line sensor or a saw resonator sensor?. Do you use PML?. Did you get the admitance of the device?. How do you plan see the frequency shift: either performing a time domain simulation or frequency domain simulation?

Can you send me your file?

Waiting for your reply.

Regards

Guillermo

PS: do you have facebook or something else so we can chat? and share the information easier.

Hi! Thanks, I already had seen that forum, but I was not able to fix my errors. Are you designing a delay line sensor or a saw resonator sensor?. Do you use PML?. Did you get the admitance of the device?. How do you plan see the frequency shift: either performing a time domain simulation or frequency domain simulation? Can you send me your file? Waiting for your reply. Regards Guillermo PS: do you have facebook or something else so we can chat? and share the information easier.

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Posted: 1 decade ago Apr 3, 2012, 12:16 p.m. EDT
Hi Guillermo,
i am doing what you are planning to do . i have a elastic diaphragm on which the subsrate beam is placed on which the saw sensor is mounted. i am giving a pessure from he bottom of the diaphragm . i will send you the design of the structure tommorow.

Regards
Rohan
Hi Guillermo, i am doing what you are planning to do . i have a elastic diaphragm on which the subsrate beam is placed on which the saw sensor is mounted. i am giving a pessure from he bottom of the diaphragm . i will send you the design of the structure tommorow. Regards Rohan

Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Apr 3, 2012, 3:59 p.m. EDT
Hi Rohan!

Ok, thank you.

I really appreciate your help with this.

Regards

Guillermo
Hi Rohan! Ok, thank you. I really appreciate your help with this. Regards Guillermo

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Posted: 1 decade ago Feb 18, 2013, 10:39 a.m. EST
Hi Guillermo,

did you worked out your PML problem? If yes, I am very interested: I am trying to model a SAW propagating on 128° YX LiNbO3 (by the way, thank you for the elastic, coupling and permittivity matrix, i could not make the rotated coordinate system work properly...); and I don't know how PML work... Did you finally understand and solve your problem?

Thanks a lot!

Sylvain
Hi Guillermo, did you worked out your PML problem? If yes, I am very interested: I am trying to model a SAW propagating on 128° YX LiNbO3 (by the way, thank you for the elastic, coupling and permittivity matrix, i could not make the rotated coordinate system work properly...); and I don't know how PML work... Did you finally understand and solve your problem? Thanks a lot! Sylvain

Guillermo Andrés Borrero Becerra

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Posted: 1 decade ago Feb 18, 2013, 3:43 p.m. EST
Hi,

In order to solve the problem with the PML's, I used rectangular structures on each side of the substrate, and then I defined them as PML, geometry type Cartesian. This way the PML's worked properly in my model.

Regards.
Hi, In order to solve the problem with the PML's, I used rectangular structures on each side of the substrate, and then I defined them as PML, geometry type Cartesian. This way the PML's worked properly in my model. Regards.

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Posted: 1 decade ago Feb 19, 2013, 3:11 a.m. EST
Hi,

Thank you for your answer, do you know what is the importance of PML scaling factor and PML order?

Regards,

Sylvain
Hi, Thank you for your answer, do you know what is the importance of PML scaling factor and PML order? Regards, Sylvain

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Posted: 1 decade ago Oct 29, 2013, 7:18 a.m. EDT
Hi:
I am designing a SAW tire pressure sensor .I added mass to the surface of the substrate,the eigenfrequency changed , I am not sure this is correct. Could you please help me check it ,thanks..
Hi: I am designing a SAW tire pressure sensor .I added mass to the surface of the substrate,the eigenfrequency changed , I am not sure this is correct. Could you please help me check it ,thanks..

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