FastFieldSolvers Forum
FastFieldSolvers Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
 All Forums
 FastFieldSolvers
 FasterCap and FastCap2
 fastercap: positive values on off-diag elements
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

spark

2 Posts

Posted - Jun 21 2019 :  01:35:35  Show Profile  Reply with Quote
Hi Enrico and other members of the forum,

I am encountering some issues running fastercap with my geometry. I am trying with simplified geometries prior to doing something more complex.

concern 1: non negative off-diagonal elements.
concern 2: asymmetric off-diagonal elements.

The input geometry looks like the images in the link below
ht*ps://imgur.com/a/OOHFKcF

- The target geometry has dimensions on the order of hundreds or thousands of micrometers, and may have feature as small as tens or hundreds of nanometers.

Since they are too small, the geometry input to the fastercap is scaled up to meters (10^6 times by length), instead of micrometers.


- the .lst file has following .txt inputs

C c1.txt 1.0 0.0 0.0 0.0
C c2.txt 1.0 0.0 0.0 0.0
C c3.txt 1.0 0.0 0.0 0.0
D Substrate.txt 1 11.9 0.0 0.0 0 0.01 0.01 0.01

where the substrate.txt defines the substrate (dielectric), with a

c1.txt defines a thin layer of conductor on top of the substrate, except for the circulr dip in the center,

c2.txt defines a boxed-shaped conductor in the center of the circular dip,

and c3.txt defines another boxed-shaped conductor in the center of the circular dip.

- I noticed that varying mesh density sometimes negative off-diagonals, but sometimes negative off-diagonals still appear in quite high mesh densities.

- Can you help me troubleshoot the issues please? I can provide the mesh files (.txt) as well

Enrico

410 Posts

Posted - Jun 27 2019 :  00:09:41  Show Profile  Reply with Quote
Hi Spark,

your question seems akin to 'tbell' user's question, see tbell's posts.

I suggest you to reduce the geometry to the simplest possible still presenting the issue, and then you can send it to me (see 'contacts' page) if you need some check.

Best Regards,
Enrico
Go to Top of Page

spark

2 Posts

Posted - Jul 16 2019 :  21:57:22  Show Profile  Reply with Quote
Hi Enrico,


I was looking for your email but I couldn't see your email due to the error:
"
Send an E-MAIL Message
Microsoft VBScript runtime error '800a000d'
Type mismatch: 'rs'
/forum/pop_mail.asp, line 228
"


I sent an email to support@fastfieldsolvers.com instead. I wish you could take a look at it.


In short, I tried changing -d parameter to account for high aspect ratio geometry and also used Galerkin scheme. Non-negative off diagonals are not appearing anymore, but I have other issues regarding the asymmetry of the off-diagonal elements and values being off from other simulation tools. I need some help on how to make it work.

edit: I may have been misinterpreting what the "overlapping panels" are. I got rid of the top panel from my "substrate.txt" in my CPW geometry and assigned different reference points for each panels for my conductors. I had some success but I hope I can still get your feedback.

Thanks,


Edited by - spark on Jul 17 2019 19:32:02
Go to Top of Page

Enrico

410 Posts

Posted - Jul 18 2019 :  00:55:13  Show Profile  Reply with Quote
Hi Sungoh,

I've received your email and answered, but I cannot immediately look at your question. However in the meanwhile I checked the "contact us" form and it seems to work fine on my side. Could you kindly check again if it works for you (possibly after flushing the browser cache)?

Best Regards,
Enrico
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
FastFieldSolvers Forum © 2018 FastFieldSolvers S.R.L. Go To Top Of Page
Powered By: Snitz Forums 2000 Version 3.4.06