Thank you for your response.  Can I change the layer dimension so that it won't go outside of the substrate dimension? How can I choose copper as for patch and ground plane from feko? what is the main difference between regular antenna with patch+substrat+ground with this planar greens functions?  Thank you in advance.

Hi Akash Moynul Hasan,

As you can see in my attached picture the infinite PEC groundplane is visualized larger than the substrate layer(s), just like in POSTFEKO. Not sure why it is different for ? Which version are you using?

Since I assume that you have no experience with Feko, I would recommend that you first watch the introduction videos and the Getting Started Guide. Then you should start building simple models from the example guide. Feko is quite intuitive and most customer learn it easily this way.

To apply copper to a face you need to add Copper from the Mediua Library to your model and then apply it to the face(s):

Best regards,
Torben

Hi Akash Moynul Hasan,

The "extra layer" that you see in POSTFEKO is a PEC ground plane you have defined in CADFEKO in the dialogue of the planar multilayer substrate:

As you can see in the picture, the ground plane is also visible in CADFEKO. The infinite groundplane can only be PEC, not copper. But of course you can also omit the inifite groundplane and define a finite surface made of copper as the groundplane instead.

Examples of how to use the planar greens functions can be found in the Example Guide. For example, open the model of Example A8.3 "Pin-fed microstrip patch antenna with Multilayer Substrate" via the Application Macro in CADFEKO:

I hope this helps!

Best regards,
Torben

Hallo Herr Hoppe,

vielen Dank für Ihre Antwort.

 

• Das heißt man hat einmal die "reale" Oberfläche und die zusätzlich eingefügte Empfangsfläche, an denen Pfade zurückgestrahlt werden können, verstehe ich das richtig?

 

• Wozu dient dieser Wert, würde es nicht ausreichen, eine Empfangsfläche pro "realer" Fläche zu haben?

 

• Und wie sollte man den Wert bei Oberflächen ohne Dicke einstellen? Hier könnte man ihn dann theoretisch so klein wie möglich wählen, schätze ich.

 

Dankeschön und beste Grüße

Julian

Guten Tag Julian,

es gibt einmal die "reale" Oberfläche, an der die Strahlen reflektiert werden, und dann zusätzlich die eingefügte Empfangsfläche, an denen die Strahlen empfangen werden.

Der Abstand ist erforderlich, um zu vermeiden, dass die zusätzlich eingefügten Empfangspunkte in der Wand liegen und deshalb nicht erreicht werden.

Bei Wänden ohne Dicke kann der Abstand klein gehalten werden, z.B. 1cm oder 1mm.

Viele Grüße,

Reiner Hoppe

Hi

I have gone through these tutorials and I am able to reproduce the examples. But if I apply the same methodology for natural convection, some problems arise such as

- unrealistic temperature

-high velocity

-particles appear just for 0.1 s and disappear suddenly

 

Please suggest how to resolve these issues.

Hi Rajani,

These issues are typically time-step related.  EDEM calculates the Rayleigh time-step and we normally recommend running at 20% of this for stability.  AcuSolve will solve at a larger time-step but we have to consider the time-step ratio between the two programs.  Often the CFD time-step is OK within the range of 10-100 times larger than the EDEM one however the large ratios can lead to instabilities like you describe.  Reducing the ratio (reducing AcuSolve time-step) should resolve this.

Time-step also detailed in the e-learning - https://learn.altair.com/course/view.php?id=176

Regards

Stephen