Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Comsol 3.5 - RF module - Eigenfrequency - Why do I have a factor ' - 2 * i * pi' ?

Please login with a confirmed email address before reporting spam

Hello,

Using Comsol 3.5 RF module with Matlab, I already found that you need to put the frequency multiplied by ' - 2 * i * pi' in the solver line (and you need to divide by the same factor the solutions you get to have the real frequencies).

The problem is now I want to import the fem structure calculated with Matlab in Comsol, to have a better vision of the solutions. But the different solutions have frequencies multiplied by ' - 2 * i * pi', whereas the same structure calculated only with Comsol has the 'right' value of frequencies.

It seems using a script is the reason for this factor, but is there a way to access the real frequencies when importing a fem structure calculated with Matlab ? I tried 'naively' to change the values of the solutions before importing, but I get the "Access to an object's fields is only permitted within its methods" error. Anyone has an idea ?

Thank You.

2 Replies Last Post 2010年11月9日 GMT-5 13:31
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2010年11月9日 GMT-5 10:23
Hi

are you sure you have selected eigenfrequency in frequency mode and not eigenvalue mode ?

--
Good luck
Ivar
Hi are you sure you have selected eigenfrequency in frequency mode and not eigenvalue mode ? -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2010年11月9日 GMT-5 13:31
Hi,

Actually, it is the exactly the opposite I should do, I need to use eigenvalues to have the real frequency values and not eigenfrequencies (I just tested, it works). But I wouldn't have thought of it if you didn't mention it, so thank you :D.

Now why the real frequency are eigenvalues and not eigenfrequencies with a Matlab script, I have no idea. At least if you know it, it works very well.



Hi, Actually, it is the exactly the opposite I should do, I need to use eigenvalues to have the real frequency values and not eigenfrequencies (I just tested, it works). But I wouldn't have thought of it if you didn't mention it, so thank you :D. Now why the real frequency are eigenvalues and not eigenfrequencies with a Matlab script, I have no idea. At least if you know it, it works very well.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.