Search found 81 matches

by PaulUK
Tue 23 Feb 2021, 15:42
Forum: Usage
Topic: Strange behavior from rectangular waveguide
Replies: 6
Views: 4647

Re: Strange behavior from rectangular waveguide

Yes, PML has been used at each end. I tried different PML lengths and still no solution. I have not tried using PEC and a finite Kappa for the waveguide yet. I can give this a try. The PML has been fine in the past when using planar transmission lines. I don't agree about the -50 dB level in real de...
by PaulUK
Tue 16 Feb 2021, 15:25
Forum: Usage
Topic: Strange behavior from rectangular waveguide
Replies: 6
Views: 4647

Re: Strange behavior from rectangular waveguide

Has no one else seen this problem?
by PaulUK
Wed 18 Nov 2020, 14:32
Forum: Usage
Topic: Strange behavior from rectangular waveguide
Replies: 6
Views: 4647

Re: Strange behavior from rectangular waveguide

openEMS with PEC boundaries in x and y directions, vacuum inside. PEC BC as WG Walls in x and y PML_8 S11_S21.png openEMS results when finite thickness model PEC is replaced with a material with conductivity "kappa". Silver PML_8 S11_S21.png End of post. I hope that someone can shed some light on th...
by PaulUK
Wed 18 Nov 2020, 14:27
Forum: Usage
Topic: Strange behavior from rectangular waveguide
Replies: 6
Views: 4647

Re: Strange behavior from rectangular waveguide

Continued images...

CST Results
CST WG20 SParameters.png
CST Results
CST WG20 SParameters.png (36.25 KiB) Viewed 4646 times
openEMS Model
3DWG20.png
openEMS model
3DWG20.png (392.81 KiB) Viewed 4646 times
openEMS Results for finite wall thickness PEC.
PML_12 S11 S21.png
openEMS Results for finite wall thickness PEC
PML_12 S11 S21.png (44.48 KiB) Viewed 4646 times
by PaulUK
Wed 18 Nov 2020, 14:24
Forum: Usage
Topic: Strange behavior from rectangular waveguide
Replies: 6
Views: 4647

Strange behavior from rectangular waveguide

I will post some images comparing a length of WG20 (WR42) simulated with both CST and openEMS. There are a number of discrepancies which I will list. I don't know if the issues are caused by incorrect use of openEMS or if it's a consequence of numerical noise or limitations of the software. I'm hopi...
by PaulUK
Sat 20 Jun 2020, 09:49
Forum: Usage
Topic: Corrugated Horn Antenna Tutorial for openEMS
Replies: 6
Views: 12140

Re: Corrugated Horn Antenna Tutorial for openEMS

Hello Paul Thanks, then it is clear. I found a typo in the middle of page 36. "-wgl-10 is the location" -> -wgl+10 Here it is correct mesh.z = [-wgl-lambda_max-9 -wgl-1 -wgl -wgl+10 0 len(1:2:z_number) length+2*lambda_max+9 ]; It is indeed +10 not -10. Thank you for pointing that out. That's anothe...
by PaulUK
Wed 17 Jun 2020, 17:50
Forum: Usage
Topic: Corrugated Horn Antenna Tutorial for openEMS
Replies: 6
Views: 12140

Re: Corrugated Horn Antenna Tutorial for openEMS

or should the "9" be inside the brackets because we speak about 9 cells/layer for MPL_8 and not about 9 mm. mesh.x = [( -a_offset(end-9) -lambda_max) -radmsh(1:4:end) 0 radmsh(1:4:end) ( a_offset(end+9) +lambda_max)]; Hello Gerald, I had a look at this and yes, the "9" would have been distance rath...
by PaulUK
Mon 15 Jun 2020, 17:56
Forum: Usage
Topic: Corrugated Horn Antenna Tutorial for openEMS
Replies: 6
Views: 12140

Re: Corrugated Horn Antenna Tutorial for openEMS

Thanks for pointing this out. It may be that the 9 can be left out all together, but I will check this once I get some time and get the computer set up again (I'm setting up after moving at the moment). It may well be an error but if so, it should have no impact on the meshing where it's important. ...
by PaulUK
Mon 15 Jun 2020, 09:23
Forum: Usage
Topic: Problem with phase accuracy in waveguide polarisers
Replies: 4
Views: 5048

Re: Problem with phase accuracy in waveguide polarisers

the answer is in your question. circular waveguide requires non-orthogonal meshing I've used the rectangular mesh with circular waveguide before, but I apply the appropriate circular waveguide port and had no problems. I didn't use the cylindrical mesh because the slots in the waveguide walls of th...
by PaulUK
Mon 15 Jun 2020, 09:18
Forum: Usage
Topic: Problem with phase accuracy in waveguide polarisers
Replies: 4
Views: 5048

Re: Problem with phase accuracy in waveguide polarisers

I shall post the examples that I have done and show their results either later or within a few days. I've just moved to Germany from the UK so things are a bit of a mess at the moment. As soon as I get my computer setup I will post what I have. I previously did these simulations with CST and HFSS an...