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12 Replies
Last post: January 30, 2012 1:34pm UTC
September 9, 2010 6:25am UTC
modeling of reflection/transmission
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
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September 9, 2010 5:18pm UTC in response to Susant Patra
Re: modeling of reflection/transmission
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
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September 10, 2010 6:35am UTC in response to Fernando Fuzinatto Dall'Agnol
Re: modeling of reflection/transmission
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
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January 30, 2011 8:03pm UTC in response to Susant Patra
Re: modeling of reflection/transmission
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.
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January 30, 2011 8:47pm UTC in response to Maximiliano Velez
Re: modeling of reflection/transmission
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
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January 30, 2011 11:50pm UTC in response to Ivar Kjelberg
Re: modeling of reflection/transmission
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
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January 31, 2011 1:33am UTC in response to Maximiliano Velez
Re: modeling of reflection/transmission
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.
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.
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February 1, 2011 8:03pm UTC in response to Fernando Fuzinatto Dall'Agnol
Re: modeling of reflection/transmission
Hi Fernando:
Could you send an email adress for contacting you?
by the way, do you speak spanish??
thank in advance.
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May 1, 2011 8:22pm UTC in response to Fernando Fuzinatto Dall'Agnol
Re: modeling of reflection/transmission
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
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May 2, 2011 5:37pm UTC in response to Gayatri Venugopal
Re: modeling of reflection/transmission
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
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May 4, 2011 5:40am UTC in response to Fernando Fuzinatto Dall'Agnol
Re: modeling of reflection/transmission
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
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May 5, 2011 3:55am UTC in response to Gayatri Venugopal
Re: modeling of reflection/transmission
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
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January 30, 2012 1:34pm UTC in response to Fernando Fuzinatto Dall'Agnol
Re: modeling of reflection/transmission
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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