There are various time depending (BDF) solvers, such as PARADISO, MUMPS, SPOOLES and Dense Matrix. Which solver we should use? Thanks.
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Meaning of time depending solvers
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How to model Surface Roughness in COMSOL 4.4?
Hi,
I would like to model a bulk acoustic microresonator and investigate the effect of the surface roughness. I have read some discussions on surface roughness, however I could not find model for COMSOL 4.4. I appreciate it is someone could help me with this.
Thanks,
Milad
I would like to model a bulk acoustic microresonator and investigate the effect of the surface roughness. I have read some discussions on surface roughness, however I could not find model for COMSOL 4.4. I appreciate it is someone could help me with this.
Thanks,
Milad
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Problem in finding reflection characteristics of silicon solar panel
I'm new Comsol, How to create a silicon solar panel (i'm using wave optics module for the creation ) . I need to apply Laser and short pulse on the substrate and find its reflection character. how to create own short pulse in comsol.
Thank you
Santhosh
Thank you
Santhosh
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Is there a variable Ex in Electromagnetic Waves module?
Dear all,
By the question in the title, I mean a variable named exactly as Ex, without emw. prefix. Is it an internal variable?
I input such a variable by mistake in a model. COMSOL didn't report an error, but the results were totally wrong. After changing to emw.Ex, the results make much more sense.
Thanks!
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Pu, ZHANG
DTU Fotonik
By the question in the title, I mean a variable named exactly as Ex, without emw. prefix. Is it an internal variable?
I input such a variable by mistake in a model. COMSOL didn't report an error, but the results were totally wrong. After changing to emw.Ex, the results make much more sense.
Thanks!
--
Pu, ZHANG
DTU Fotonik
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how to do the research on Luminous efficiency about the LED andLED Package
I am a rookie in the simulation on the Luminous efficiency about the LED andLED Package,I need some Model and cases to study the efficiency and external quantum efficiency ，and also want to know how to study the Material and the light decay phenomenon along it working time .Please help ,thank you for your reading and I am very looking forward to get the answer
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Far field projection of heterogeneous environment
Hi all,
I am interested in far field distribution of scatterers placed over substrates. If I want to know the far field distributions of these kind of heterogeneous structures, will COMSOL give me correct distribution just by including inbuilt far field calculation node. If I want to see only leakage radiation through substrate, what should I do??
I am interested in far field distribution of scatterers placed over substrates. If I want to know the far field distributions of these kind of heterogeneous structures, will COMSOL give me correct distribution just by including inbuilt far field calculation node. If I want to see only leakage radiation through substrate, what should I do??
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Thin film
can any one help me for calculation of transmittance and reflectance of a thin film
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optical mode analysis with the geometry affected by mechanical force
I'm doing optical mode analysis given that the geometry of my structure is deformed by mechanical force. The displacement can be easily calculated.
THE question is how to calculate the optical mode with the deformed structure (this structure is the calculated results and cann't be plotted manually).
THE question is how to calculate the optical mode with the deformed structure (this structure is the calculated results and cann't be plotted manually).
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Impedance in RF module & Transmission Line module
Hi !
I am currently on a project. I am trying to model human liver and the reaction of tissues due to the heat. There are models already set up in COMSOL. They are called "tumor_ablation" and "microwave_cancer_therapy" and they are placed in the " Heat transfert module" library.
It's the exact thing that I want but I would like to upgrade it.
I have an electrical modeling of liver, that let me know the impedance in function of the frequency.
So my objective is to use the geometric of the "tumor_ablation" model, using the "microwave_cancer_therapy" physics (especially the RF module), changing the impedance of tissues by my function.
1) Is it possible ? (I mean to change the impedance by my function )
1 bis) Is it possible using the Transmission Line module?
2) If yes , how ?
Thanks for your consideration, it's the first time that I meet this software so I just know few things that I have learned watching COMSOL videos.
I am currently on a project. I am trying to model human liver and the reaction of tissues due to the heat. There are models already set up in COMSOL. They are called "tumor_ablation" and "microwave_cancer_therapy" and they are placed in the " Heat transfert module" library.
It's the exact thing that I want but I would like to upgrade it.
I have an electrical modeling of liver, that let me know the impedance in function of the frequency.
So my objective is to use the geometric of the "tumor_ablation" model, using the "microwave_cancer_therapy" physics (especially the RF module), changing the impedance of tissues by my function.
1) Is it possible ? (I mean to change the impedance by my function )
1 bis) Is it possible using the Transmission Line module?
2) If yes , how ?
Thanks for your consideration, it's the first time that I meet this software so I just know few things that I have learned watching COMSOL videos.
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Getting scattered field from magnetic current
Hello,
i'm trying to figure to out how to get the scattered field from a magnetic current excitation.
The model is 2D, I have a arbitrary object. Then I assign a point to be magnetic current excitation. The magnetic current generates spherical wave with TM polarization. Is there a way to get the scattered field instead of the full field? or the only option i have is the define this spherical TM wave as the background field?
i'm trying to figure to out how to get the scattered field from a magnetic current excitation.
The model is 2D, I have a arbitrary object. Then I assign a point to be magnetic current excitation. The magnetic current generates spherical wave with TM polarization. Is there a way to get the scattered field instead of the full field? or the only option i have is the define this spherical TM wave as the background field?
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Setting up plane wave
Hi, I am quite new to comsol. My problem is fairly simple. I want to simulate an incident plane wave in 2D using RF module and calculate Fresnel Reflection and Transmission coefficients.
However, I am not sure to setup a plane wave travelling in x-direction. I used exp(-i*k*x) in port settings and chose E-field as input.
I have used a rectangular geometry and setup a port. But I am getting a Gaussian wave rather than a plane wave.
Help would be much appreciated.
Regards
However, I am not sure to setup a plane wave travelling in x-direction. I used exp(-i*k*x) in port settings and chose E-field as input.
I have used a rectangular geometry and setup a port. But I am getting a Gaussian wave rather than a plane wave.
Help would be much appreciated.
Regards
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Expression for microwave absorbed power by plasma
Hi
My work is on mw excited plasma. I want to know that how much mw power is absorbed by the plasma. So which expression, I should use?
Thanking you.
My work is on mw excited plasma. I want to know that how much mw power is absorbed by the plasma. So which expression, I should use?
Thanking you.
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RCS problem in 3D model
Hello!
First of all, I need to let you know that I am a total beginner in these simulations so please be gentle :)
I am trying to solve RCS for a 3D module by following a tutorial for a 2D RCS of a boat: www.comsol.com/model/download/...els.rf.radar_cross_section.pdf
The problem I am having is primarily with strange looking electric field that I simulated so I think that I probably did the expression wrong. That is the main reason why I suspect that the plotted Far field is also faulty. My goal is to make RCS of a given mesh 360 degrees in both horizontal and vertical planes. What am I doing wrong?
I am posting my file here with this post. Unfortunately the file is 18MBs so I cant post it here. I tried to post java file but this forum does not let me:
dropfile.to/73pU3
First of all, I need to let you know that I am a total beginner in these simulations so please be gentle :)
I am trying to solve RCS for a 3D module by following a tutorial for a 2D RCS of a boat: www.comsol.com/model/download/...els.rf.radar_cross_section.pdf
The problem I am having is primarily with strange looking electric field that I simulated so I think that I probably did the expression wrong. That is the main reason why I suspect that the plotted Far field is also faulty. My goal is to make RCS of a given mesh 360 degrees in both horizontal and vertical planes. What am I doing wrong?
I am posting my file here with this post. Unfortunately the file is 18MBs so I cant post it here. I tried to post java file but this forum does not let me:
dropfile.to/73pU3
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Plotting unit length as a function of the angle of incidence
I am having trouble with presenting a polar plot for the RCS per unit length as a function of the angle of incidence for 3D model.
If the expression for plotting the said RCS for the 2D model would be:
10*log10(2*pi*abs(Efarz(cos(phideg[deg]),sin(phideg[deg]))))
then how would it go for the 3D model?
If the expression for plotting the said RCS for the 2D model would be:
10*log10(2*pi*abs(Efarz(cos(phideg[deg]),sin(phideg[deg]))))
then how would it go for the 3D model?
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How to add a condition on the mode solver when using the parametric sweep?
Hi,
I am using the RF module of COMSOL 4.3b to determine the effective refractive index of the modes of a waveguide as a function of the wavelength (for instance between 600 and 700 nm). I am therefore using the parametric sweep in wavelength and then run the mode analysis to have the effective index for each wavelength.
For the fundamental mode it works well. I first do a modal analysis for the initial wavelength to determine the initial effective index and be able to complete the "search for modes around". Then I run the modal analysis and the effective indices in all the wavelength range correspond to the fundamental mode.
So this method works for the fundamental mode because its effective index varies quite slowly with the wavelength and all the results are still around the initial "search for modes around". However I have some troubles with the first order mode, if I do a parameter sweep of more than 5 nm the resulting effective index are not the ones of the first order mode anymore. And this is because of the condition "search for modes around" that limits the result around this value and prevent the software to look for lower indices.
So my question is: can I add a condition on the mode solver when doing wavelength sweep? For instance instead of always having the same value for "search for modes around", would it be possible to make the software use the last effective index obtained as a starting point for the next calculation?
Or to add a condition on the consecutive results such as neff (i+1) < neff (i)?
Thank you!
I am using the RF module of COMSOL 4.3b to determine the effective refractive index of the modes of a waveguide as a function of the wavelength (for instance between 600 and 700 nm). I am therefore using the parametric sweep in wavelength and then run the mode analysis to have the effective index for each wavelength.
For the fundamental mode it works well. I first do a modal analysis for the initial wavelength to determine the initial effective index and be able to complete the "search for modes around". Then I run the modal analysis and the effective indices in all the wavelength range correspond to the fundamental mode.
So this method works for the fundamental mode because its effective index varies quite slowly with the wavelength and all the results are still around the initial "search for modes around". However I have some troubles with the first order mode, if I do a parameter sweep of more than 5 nm the resulting effective index are not the ones of the first order mode anymore. And this is because of the condition "search for modes around" that limits the result around this value and prevent the software to look for lower indices.
So my question is: can I add a condition on the mode solver when doing wavelength sweep? For instance instead of always having the same value for "search for modes around", would it be possible to make the software use the last effective index obtained as a starting point for the next calculation?
Or to add a condition on the consecutive results such as neff (i+1) < neff (i)?
Thank you!
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Modeling of resonant absorbtion
Hello,
I am wondering if it is possible for COMSOL to model the resonant absorption of protons in a static magnetic field.
For example, if I had a 1T field along the Z-axis with a water phantom inside, I would expect to see resonant absorption if I applied a 42.58 MHz RF pulse at 90 degrees to the Z-axis.
I am currently working on modeling this and would just like to know if such a thing is possible.
Thank you
I am wondering if it is possible for COMSOL to model the resonant absorption of protons in a static magnetic field.
For example, if I had a 1T field along the Z-axis with a water phantom inside, I would expect to see resonant absorption if I applied a 42.58 MHz RF pulse at 90 degrees to the Z-axis.
I am currently working on modeling this and would just like to know if such a thing is possible.
Thank you
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How to set up the port?
Dear all,
I use RF module constructing 2 models, which have same structures except the length. The input power and other parameters are also the same. But after simulation, the power at the incident port of both models are not equal. I want them to have a same value in order to compare the wave and study the dissipate power along distance. I already use a scattering BC. The characteristic are similar but still not equal. So, I wonder that is there any way to set up the structure to have a same input power after the simulation?
Thank you in advance
I use RF module constructing 2 models, which have same structures except the length. The input power and other parameters are also the same. But after simulation, the power at the incident port of both models are not equal. I want them to have a same value in order to compare the wave and study the dissipate power along distance. I already use a scattering BC. The characteristic are similar but still not equal. So, I wonder that is there any way to set up the structure to have a same input power after the simulation?
Thank you in advance
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microfluidic + external force field (optical force)
Hi, everybody
I am a new user and just learned the tutorial of particle separation in microfluidics (www.comsol.com/model/red-blood-cell-separation-17013).
I am working on a problems that how the particle motion will be deviated by an external force field, may I know how to do the modification from that tutorial?
This force is generated from an external electromagnetic wave, so called optical force. If I want to further include the RF module and do the whole simulation, are there any samples I can follow please? thank you!
I am a new user and just learned the tutorial of particle separation in microfluidics (www.comsol.com/model/red-blood-cell-separation-17013).
I am working on a problems that how the particle motion will be deviated by an external force field, may I know how to do the modification from that tutorial?
This force is generated from an external electromagnetic wave, so called optical force. If I want to further include the RF module and do the whole simulation, are there any samples I can follow please? thank you!
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Thermoacoustic imaging
I am working on doing microwave induced Thermoacoustic imaging simulation , i wonder if comsol have a special module to deal with converting the heat variation with time to an acoustic waves because i couldnt find any time domain solver for the thermoacoustic phenomena in comsol, do anybody have any suggestion regarding my problem, or is it better to build my own module using PDE module
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How to draw a periodic waveguide?
Hi all,
I have a simple question towards for geometry for which I didn't a lot of search but still confused.
So how do you draw a periodic waveguide that has a simple mathematical expression in 3D?
For example, in this blog of corrugated waveguide
www.comsol.com/blogs/computing...mpedance-corrugated-waveguide/
I was looking for some "nonlinear extrusion", but didn't see it.
It would be so nice of you if you could give me a quick answer even with one keyword.
Best,
Cathy
P.S. I think this would be less version related, but I'm using 4.3a
I have a simple question towards for geometry for which I didn't a lot of search but still confused.
So how do you draw a periodic waveguide that has a simple mathematical expression in 3D?
For example, in this blog of corrugated waveguide
www.comsol.com/blogs/computing...mpedance-corrugated-waveguide/
I was looking for some "nonlinear extrusion", but didn't see it.
It would be so nice of you if you could give me a quick answer even with one keyword.
Best,
Cathy
P.S. I think this would be less version related, but I'm using 4.3a
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