3.5 - Latest Discussions - COMSOL Forums

3db coupler

Mon, 21 May 2012 12:22:43 +0000

How to design 3db directional coupler.

Directional coupler

Mon, 21 May 2012 12:21:54 +0000

How to design directional coupler with 0.5 coupling coefficient using COMSOL softeare.

Nonlinear electric conductivity

Thu, 17 May 2012 08:18:31 +0000

Hi,

I'm currently working on electrical transients simulation using AC/DC module. How can I define nonlinear electric conductivity of zinc oxide (ZnO) in subdomain settings?

Thank you

1by2 directional coupler and 2by1 directional coupler

Wed, 16 May 2012 14:09:01 +0000

1by2 directional coupler means that given input is split into two outputs and also the two outputs are in 90degrees phase shift with each other,how can i geometrical design the 1by2 and also 2by1 directional coupler using COMSOL software.

90 degrees phase shift

Wed, 16 May 2012 04:21:41 +0000

There are two inputs and two outputs to microring resonator, in that two inputs, one input i will give directly and i want ton give another input with 90 degrees phase shift ,how can i give

Error 9040 NullPointerException

Tue, 15 May 2012 15:31:29 +0000

Hi
When I wanted to insert some constants,this error happened..the version of my comsol is 3.5...how can i solve the error?
Tanx so much

Convergence issue when simulating harmonic propagation with assemblies (3D)

Tue, 15 May 2012 00:34:16 +0000

Hi,
I want to model harmonic propagation through a 3D multilayer. We use the rf module of comsol 3.5. We enclose the geometry, which is essentially a quarter of an inverted square-based pyramid, with PML at the top, and use perfect magnetic and electric conductor on each pair of parallel side boundaries. As we make the wave to enter through an inner boundary we create a pair and thus, we use assemblies for that. The problem is the slow convergence, in case it happens to converge. We follow the instructions of the rf user guide regarding copying the meshes at each side of the pair in order to avoid using the Vanka preconditioner. We checked the rest of the model by removing the top PML and making the wave to enter through the top boundary, and the model is solved within a decent period of time. Can you help me with some tips to speed up convergence in case we use assemblies?
Thanks a lot.

Relative Permeability

Mon, 07 May 2012 21:55:58 +0000

Dear users.

Please, I request your help to enter an equation of variation of μr depending on B.
I do not want to enter other material in the library and edit a curve B x H. I would like to use the appropriate space to insert the value of μr. I was able to enter multiple equations there but do not know the proper format for entering μr depending on B. What is the proper formatting? You can send me an example?

Thanks a lot.

Att. Paulo Tibúrcio

Design of two two microring resonators with input of a two 1by2 directional couplers

Mon, 07 May 2012 15:30:00 +0000

Instead of giving input directly to the micro-ring resonators, i am using two 1by2 directional couplers and one output of directional coupler is connected to the first input of the microring resonator and second output of the directional coupler is connected to the input of the another microring resonator. After that using another 1by2 dorectional coupler ,out of these two outputs one output is connected to the second input of the micro-ring resonator and second output is connected to the second input of the second microring resonator. Please explain how to design geometrically these procedure by using COMSOL software.

1by2 directional coupler

Mon, 07 May 2012 15:14:53 +0000

I want to geometrical design the 1by2 directional coupler,here in MATLAB i used coupling coefficient as a 0.5 that means if i give input it has to divide into two parts ,thw two parts would be 50% of input and 50% of input. How to implement these 1by2 directional coupler with coupling coefficient 0.5(50%) using COMSOL software.

waveguide power flow transmission

Mon, 07 May 2012 05:45:46 +0000

Hi, all

I'm designing a device coupled with a straight waveguide right now. I used port 1 and port 2 for the input and output of the waveguide, and would like to obtain the power flow transmission from the output port. I excited the input port as single mode TE wave, and solve the two ports by boundary mode analysis. I integrate the power flow at output port boundary and obtain the transmission. But I would like to know if I integrate the power flow at the input boundary, is the value means the reflection? I suppose that the port boundary doesn't include the reflection waves, is that right?

Thank you so much and look forward to the answer.

Question about the microring simulations.

Sun, 06 May 2012 06:29:35 +0000

Hi,

I didn't mention about my email address which is as follows:
photon.ktlee@gmail.com

Thanks so much.

Best regards,

Kitae

Question about the microring simulation.

Sun, 06 May 2012 06:17:45 +0000

Hi Jiawei,

I am trying to run some simulations to see the optical field distribution of the microring resonator.
But, I couldn't get any reasonable results yet from the calculation.
The PDE weak form, subdomain module was employed for the simulation.

When I saw your discussion, it seems that you already finished some parts of the microring simulation, right?
What kinds of module did you use for that?

If you don't mind, could you please send the .mph file of the microring to examine it by myself?

Thanks a lot for your kind consideration in advance.

Best wishes,

Kyu-Tae

loss factor

Sat, 05 May 2012 12:29:29 +0000

Hi,

Is the loss factor in COMSOl the same with the viscosity factor?
I got the viscosity factor of silicon( as in the attachment) . And i want to use thest datas to calculate the Q factor of a MEMS resonator.

How can I do it? Can I directly consider the datas as loss factor in comsol?
Thanks!

Jun

crystal growth

Mon, 30 Apr 2012 20:53:55 +0000

how do i solve melt-crystal interface? and then how analyses stress and casting velocity?

Physics in 3D after revolution of a 2D plane

Fri, 27 Apr 2012 13:10:29 +0000

Hi,

Using Fluid Dynamics I want to create a 3D geometry by revolving a 2D plane. If I do so, it is not possible to change the boundary and subdomain settings in physics. (You can't click on these options they are grey). Even for simple geometries like a cylinder made by revolving a 2D plane this is not possible.
Is there somting I have to adjust after revolve a 2D geometry to 3D bevore I can change the subdomain and boundary settings in 3D?

Thanks, Til

Why sometimes the subdomain option is locked?

Wed, 25 Apr 2012 14:44:11 +0000

Hello

I am working with the Comsol Multiphysics 3.5. The scope of my work is the simulation of the absorption of hydrogen in a metal hydride bed. When i go to equation system-subdomain setting (cntl+F8) and change some variables at the variables toolbar, a picture with a locker appears? why does this happens?? And of course this is affect the whole system??

Thank you very much!

moving mesh ALE

Fri, 20 Apr 2012 12:34:23 +0000

Hi every one. I need some help to blend both of two things.

I am working on some project on COMSOL.

I am trying to simulate the effect of eddy current from moving magnet to solid conductivity material.

Permanent magnet moving by spring using the structural mechanics module. And I added emqa (quasi-statics, Magnetic / Perpendicular Induction Currents, Vector Potential) and gave some data of permanent magnet and conductivity material, and they located in the separated air gap.
Then I need to blend both of them. I am trying to use moving mesh (ALE).
But I can not find out how to solve emqa system.

Thanks.

Particle tracing

Sat, 30 Jul 2011 16:32:34 +0000

I have hard time using particle tracing,

without mass in particle tracing is fine,

but if I put the mass on particle tracing,

the streamline(particle) itself, doesn't move at all,

I don't know the reason why,

I am using comsol 3.5 also, Multiphysics in fluid mechaincs in steady state condition

and I think there are not a lot of example regarding particle tracing,

if someone does have some,

I will be happy if someone shares with me,

thanks a lot have a great day :)

Coupling to a ring resonator

Thu, 17 Mar 2011 21:04:04 +0000

Hi,

I am having trouble with coupling from a waveguide to a ring resonator. Light is guided along the waveguide however it is not coupled to the ring resonator (the gap is close enough). How should I define the boundary conditions? I basically would like to see the spectrum of the ring resonator. Is it possible in Comsol?

thanks,
Damla