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modeling of reflection/transmission

Posted 09.09.2010, 02:25 GMT-4 RF & Microwave Engineering Version 3.5a 12 Replies

Susant Patra
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Hi,

I want to model two unbounded area separated by a plane. I want to define TE wave directed at angle to the interface and observe reflection/transmission.

I would appreciate if any one can help me modeling this problem in 2D.

Regards,
Susant
12 Replies Last Post 30.01.2012, 08:34 GMT-5
Fernando F. Dall`Agnol
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Posted: 1 decade ago 09.09.2010, 13:18 GMT-4
Hi Susant,
If you don't have the RF module it is still possible to simulate reflection and transmission, but I don't know how to make it, sorry.

Now, if you do have the RF module, I suggest you to follow the tutorial model of Comsol I attached here. You can have more information at www.comsol.com/showroom/gallery/6141/ . Maybe you will have to be under subscription to acess the files.

Best Regards, Fernando
Hi Susant, If you don't have the RF module it is still possible to simulate reflection and transmission, but I don't know how to make it, sorry. Now, if you do have the RF module, I suggest you to follow the tutorial model of Comsol I attached here. You can have more information at http://www.comsol.com/showroom/gallery/6141/ . Maybe you will have to be under subscription to acess the files. Best Regards, Fernando
Susant Patra
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Posted: 1 decade ago 10.09.2010, 02:35 GMT-4
Hi Fernado,

Thanks for the comsol files. Unfortunately, every time, I try to load the 2D model inCOMSOL 4.0,. It says some kind of error occured. However, 3D model woked nicely.

Thank you very much for your help.

Regards.
Susant
Hi Fernado, Thanks for the comsol files. Unfortunately, every time, I try to load the 2D model inCOMSOL 4.0,. It says some kind of error occured. However, 3D model woked nicely. Thank you very much for your help. Regards. Susant
Maximiliano Velez
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Posted: 1 decade ago 30.01.2011, 15:03 GMT-5
Hi Fernando:
You have a file (for instance, power point) where they explain the procedure for modeling of reflection/transmission. I am working in a similar thesis project.

thanks in advance.
Hi Fernando: You have a file (for instance, power point) where they explain the procedure for modeling of reflection/transmission. I am working in a similar thesis project. thanks in advance.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 30.01.2011, 15:47 GMT-5
Hi

have you checked the model library ? there is not directly what you are looking for, but almost. Then you should really see with your rep to upgrade to 4.1 ad patch it to lastest status, then you will get far more working examples too for the model library

--
Good luck
Ivar
Hi have you checked the model library ? there is not directly what you are looking for, but almost. Then you should really see with your rep to upgrade to 4.1 ad patch it to lastest status, then you will get far more working examples too for the model library -- Good luck Ivar
Fernando F. Dall`Agnol
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Posted: 1 decade ago 30.01.2011, 18:50 GMT-5
Hi Ivar,
Yes, I've been looking and there is one indeed (model 6141). It turns out that this model does not work in 4.x. And 3.5 doesnt account for lossy media. So, I'm waiting for a hot fix. Thank you for your attention.
Cheers, Fernando.




Hi

have you checked the model library ? there is not directly what you are looking for, but almost. Then you should really see with your rep to upgrade to 4.1 ad patch it to lastest status, then you will get far more working examples too for the model library

--
Good luck
Ivar


Hi Ivar, Yes, I've been looking and there is one indeed (model 6141). It turns out that this model does not work in 4.x. And 3.5 doesnt account for lossy media. So, I'm waiting for a hot fix. Thank you for your attention. Cheers, Fernando. [QUOTE] Hi have you checked the model library ? there is not directly what you are looking for, but almost. Then you should really see with your rep to upgrade to 4.1 ad patch it to lastest status, then you will get far more working examples too for the model library -- Good luck Ivar [/QUOTE]
Fernando F. Dall`Agnol
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Posted: 1 decade ago 30.01.2011, 20:33 GMT-5
Max,
The models that I have are much like the ones I sent to Suzant. You can download them in the message I did to her above. Also go to www.comsol.com/showroom/gallery/6141/ for the tutorial. You can start with them and If you have any questions fell free to send them my way.
Yours, Fernando.


Hi Fernando:
You have a file (for instance, power point) where they explain the procedure for modeling of reflection/transmission. I am working in a similar thesis project.

thanks in advance.


Max, The models that I have are much like the ones I sent to Suzant. You can download them in the message I did to her above. Also go to http://www.comsol.com/showroom/gallery/6141/ for the tutorial. You can start with them and If you have any questions fell free to send them my way. Yours, Fernando. [QUOTE] Hi Fernando: You have a file (for instance, power point) where they explain the procedure for modeling of reflection/transmission. I am working in a similar thesis project. thanks in advance. [/QUOTE]
Maximiliano Velez
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Posted: 1 decade ago 01.02.2011, 15:03 GMT-5
Hi Fernando:

Could you send an email adress for contacting you?

by the way, do you speak spanish??

thank in advance.
Hi Fernando: Could you send an email adress for contacting you? by the way, do you speak spanish?? thank in advance.
Gayatri Venugopal
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Posted: 1 decade ago 01.05.2011, 16:22 GMT-4
Hi Fernando,

I am also trying to model the transmission and reflection in TM mode for periodic structures. I did follow Brewester angle example , and I am able to get the exact results which they have got. How ever when I use pairs as they mentioned for my case, it alters the way light interacts with the medium and I am not getting the exact results as I wanted.

So I removed the pairs and I tried running the simulation. So basically right now instead of using port boundary conditions at the pairs, I use scattering boundary condition with H=1 ( for plane wave) and integrate the avg power across the two boundaries to find transmission and reflection. However , even tho my structure responds correctly to light, howevder my transmission and reflection is almost around 0.5 . My transmission never goes around 1. It is always around 0.5.
Do you know how I can resolve it?

Thanks
Gayatri
Hi Fernando, I am also trying to model the transmission and reflection in TM mode for periodic structures. I did follow Brewester angle example , and I am able to get the exact results which they have got. How ever when I use pairs as they mentioned for my case, it alters the way light interacts with the medium and I am not getting the exact results as I wanted. So I removed the pairs and I tried running the simulation. So basically right now instead of using port boundary conditions at the pairs, I use scattering boundary condition with H=1 ( for plane wave) and integrate the avg power across the two boundaries to find transmission and reflection. However , even tho my structure responds correctly to light, howevder my transmission and reflection is almost around 0.5 . My transmission never goes around 1. It is always around 0.5. Do you know how I can resolve it? Thanks Gayatri
Fernando F. Dall`Agnol
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Posted: 1 decade ago 02.05.2011, 13:37 GMT-4
Hi Gayatri,
I suppose you're using version 3.5. To evaluate the trasmission or the reflection you have to normalize the integrated irradiance. For instance

T=abs(integral(nPoav))/Incident power.

How are you calculating the incident power? My tip is to use Pinc=mi0 H^2 c0 A cos(theta)/(2n)
mi0 is the magnetic permeability in vacuum, c0 is the speed of light in vaccum, A is the area irradiated, theta is the incident angle and n is the index of refraction of your media. Be sure you didn't miss that factor 1/2, which may be a good reason why your transmission is always around 0.5.

Please come back to me if this doesn't help.
Yours, Fernando.





Hi Fernando,

I am also trying to model the transmission and reflection in TM mode for periodic structures. I did follow Brewester angle example , and I am able to get the exact results which they have got. How ever when I use pairs as they mentioned for my case, it alters the way light interacts with the medium and I am not getting the exact results as I wanted.

So I removed the pairs and I tried running the simulation. So basically right now instead of using port boundary conditions at the pairs, I use scattering boundary condition with H=1 ( for plane wave) and integrate the avg power across the two boundaries to find transmission and reflection. However , even tho my structure responds correctly to light, howevder my transmission and reflection is almost around 0.5 . My transmission never goes around 1. It is always around 0.5.
Do you know how I can resolve it?

Thanks
Gayatri


Hi Gayatri, I suppose you're using version 3.5. To evaluate the trasmission or the reflection you have to normalize the integrated irradiance. For instance T=abs(integral(nPoav))/Incident power. How are you calculating the incident power? My tip is to use Pinc=mi0 H^2 c0 A cos(theta)/(2n) mi0 is the magnetic permeability in vacuum, c0 is the speed of light in vaccum, A is the area irradiated, theta is the incident angle and n is the index of refraction of your media. Be sure you didn't miss that factor 1/2, which may be a good reason why your transmission is always around 0.5. Please come back to me if this doesn't help. Yours, Fernando. [QUOTE] Hi Fernando, I am also trying to model the transmission and reflection in TM mode for periodic structures. I did follow Brewester angle example , and I am able to get the exact results which they have got. How ever when I use pairs as they mentioned for my case, it alters the way light interacts with the medium and I am not getting the exact results as I wanted. So I removed the pairs and I tried running the simulation. So basically right now instead of using port boundary conditions at the pairs, I use scattering boundary condition with H=1 ( for plane wave) and integrate the avg power across the two boundaries to find transmission and reflection. However , even tho my structure responds correctly to light, howevder my transmission and reflection is almost around 0.5 . My transmission never goes around 1. It is always around 0.5. Do you know how I can resolve it? Thanks Gayatri [/QUOTE]
Gayatri Venugopal
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Posted: 1 decade ago 04.05.2011, 01:40 GMT-4
Hi Fernando,

Thanks for the quick response. I tried following your suggestion and then I realised, that it actually takes a weird value for integral (nPoavg), across the boundaries. If I calculate my Pinc as you mentioned, it will be a constant ( since I am using a plane wave), and so, I end up getting a weird plot for T ( since P_t2d and P_r2d.. are both not right.. my answer for T and R also ends up being not right!)


Originally I was calculating, P_r2d and P_t2d at the boundaries, and I was doing P_tot=P_r+P_t and then T= P_t/P_tot and R=P_r/P_tot and somehow it was cancelling all the terms, and giving me a plot which is around 0.5 . However now that I am implementing Pinc, I am getting a totally random plot. I am attaching the plot of nPoavg, for your reference.

And yes, I am using 3.5.

Thanks a lot for your help
Gayatri
Hi Fernando, Thanks for the quick response. I tried following your suggestion and then I realised, that it actually takes a weird value for integral (nPoavg), across the boundaries. If I calculate my Pinc as you mentioned, it will be a constant ( since I am using a plane wave), and so, I end up getting a weird plot for T ( since P_t2d and P_r2d.. are both not right.. my answer for T and R also ends up being not right!) Originally I was calculating, P_r2d and P_t2d at the boundaries, and I was doing P_tot=P_r+P_t and then T= P_t/P_tot and R=P_r/P_tot and somehow it was cancelling all the terms, and giving me a plot which is around 0.5 . However now that I am implementing Pinc, I am getting a totally random plot. I am attaching the plot of nPoavg, for your reference. And yes, I am using 3.5. Thanks a lot for your help Gayatri

Attachments:

Fernando F. Dall`Agnol
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Posted: 1 decade ago 04.05.2011, 23:55 GMT-4
Hi Gayatri,
I saw your graphic and I must say it is ugly. Unfortunately I cannot halp you as I'd like to because I uninstalled v 3.5 from my computer. Try to track what is going wrong as follows: set all index of refraction = 1 so that you expect R=0 ant T=1, also, check the plot of Ex or Ez and see if that is a plane wave. Check if the inclination of the wave is in accordance to the angle theta. In postprocessing try a bounary integration of nPoav and see if that is in accordance with Pinc. You will probably find something.

Good luck,
Fernando.


Hi Fernando,

Thanks for the quick response. I tried following your suggestion and then I realised, that it actually takes a weird value for integral (nPoavg), across the boundaries. If I calculate my Pinc as you mentioned, it will be a constant ( since I am using a plane wave), and so, I end up getting a weird plot for T ( since P_t2d and P_r2d.. are both not right.. my answer for T and R also ends up being not right!)


Originally I was calculating, P_r2d and P_t2d at the boundaries, and I was doing P_tot=P_r+P_t and then T= P_t/P_tot and R=P_r/P_tot and somehow it was cancelling all the terms, and giving me a plot which is around 0.5 . However now that I am implementing Pinc, I am getting a totally random plot. I am attaching the plot of nPoavg, for your reference.

And yes, I am using 3.5.

Thanks a lot for your help
Gayatri


Hi Gayatri, I saw your graphic and I must say it is ugly. Unfortunately I cannot halp you as I'd like to because I uninstalled v 3.5 from my computer. Try to track what is going wrong as follows: set all index of refraction = 1 so that you expect R=0 ant T=1, also, check the plot of Ex or Ez and see if that is a plane wave. Check if the inclination of the wave is in accordance to the angle theta. In postprocessing try a bounary integration of nPoav and see if that is in accordance with Pinc. You will probably find something. Good luck, Fernando. [QUOTE] Hi Fernando, Thanks for the quick response. I tried following your suggestion and then I realised, that it actually takes a weird value for integral (nPoavg), across the boundaries. If I calculate my Pinc as you mentioned, it will be a constant ( since I am using a plane wave), and so, I end up getting a weird plot for T ( since P_t2d and P_r2d.. are both not right.. my answer for T and R also ends up being not right!) Originally I was calculating, P_r2d and P_t2d at the boundaries, and I was doing P_tot=P_r+P_t and then T= P_t/P_tot and R=P_r/P_tot and somehow it was cancelling all the terms, and giving me a plot which is around 0.5 . However now that I am implementing Pinc, I am getting a totally random plot. I am attaching the plot of nPoavg, for your reference. And yes, I am using 3.5. Thanks a lot for your help Gayatri [/QUOTE]
Weijian Ng
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Posted: 1 decade ago 30.01.2012, 08:34 GMT-5
Hi,

Can anyone help to upload this file --->
brewstersAngle3DTE.mph (6.7 MB) *
brewstersAngle2D.mph (1.2 MB) *
brewstersAngle3D_TM.mph (4.8 MB) *

As I've registered for trial license but is still waiting so i can't download.

And will anyone explain to me what is the main purpose in doing this 3 files, it is to calculate the transmitted and reflected waves only? What are the functions of the ports and boundaries, as indicated in the step by step powerpoint guide? --->
brewstersAngle3DTE.mph (6.7 MB) *
brewstersAngle2D.mph (1.2 MB) *
brewstersAngle3D_TM.mph (4.8 MB) *

Can it relates to microfluidic flow, use to detect certain specimens like viruses to differentiate by looking at the different extinctions of peaks of resulted graphs.


As I'm doing my final year project on this but it's quite difficult for me to understand this which is very confusing, and hoping that anyone can give a clearer guidance to me. I would appreciate any help.

Thank you so much !!
Hi, Can anyone help to upload this file ---> brewstersAngle3DTE.mph (6.7 MB) * brewstersAngle2D.mph (1.2 MB) * brewstersAngle3D_TM.mph (4.8 MB) * As I've registered for trial license but is still waiting so i can't download. And will anyone explain to me what is the main purpose in doing this 3 files, it is to calculate the transmitted and reflected waves only? What are the functions of the ports and boundaries, as indicated in the step by step powerpoint guide? ---> brewstersAngle3DTE.mph (6.7 MB) * brewstersAngle2D.mph (1.2 MB) * brewstersAngle3D_TM.mph (4.8 MB) * Can it relates to microfluidic flow, use to detect certain specimens like viruses to differentiate by looking at the different extinctions of peaks of resulted graphs. As I'm doing my final year project on this but it's quite difficult for me to understand this which is very confusing, and hoping that anyone can give a clearer guidance to me. I would appreciate any help. Thank you so much !!

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