substrate in ADS software

[nafah]

Hello

I have a substrate with dimensions 60mm×80mm

How does to determine the dimensions of the substrate in ADS ?

 

[volker_muehlhaus]

How does to determine the dimensions of the substrate in ADS ?

Substrate size is simulated as infinite.

 

[saeedbayanlou]

Substrate size is simulated as infinite.

Do you mean there is no way to define finite substrates?

 

[volker_muehlhaus]

Do you mean there is no way to define finite substrates?

For the Momentum solver, there is no way to define finite size substrates. This is true for other planar solvers as well.
If you use ADS with the Agilent FEM solver, you could similate finite substrate size.

Note that simulating finite substrate size is not required in most cases, and there are many other, more important details which determine the accuracy of the EM simulation.

 

[jiboune256]

Hi,
You can define finite microstrip/CPW substrate in Momentum. Just need to build the right stack-up with "open" boundaries at the top and bottom instead of "closed" at the bottom (in the Substrate Editor). You then have to use the appropriate ports instead of the default single-mode ones.
Cheers,
JB

 

[volker_muehlhaus]

@jiboune256, you refer to the substrate height (z-dimension). The question from nafah was about finite size in x-y direction.

 

[jiboune256]

@volker_muehlhaus, i understood it was finite in X-Y. Please refer to the screenshot I attached. It is maybe more explicit than my previous explanation ...


---------- Post added at 15:19 ---------- Previous post was at 15:16 ----------

I forgot to post the screenshot with the right tab in Substrate Editor -> the stack-up is like this:
FreeSpace
------ -STRIP- cond
TLY-5
------ -STRIP- cond2
FreeSpace_0

 

[volker_muehlhaus]

@jiboune256, you misunderstood the image that is shown. With the MoM method that is used, the x-y substrate size is always infinite. Even if you draw a finite ground size, the substrate size is infinite. The image shows a finite size, but that is only a simplified image and not what the solver does.

 

[jiboune256]

@volker_muehlhaus: You are definitely right, the MoM method is based on the asumption that the substrate is infinite and treats the example I showed above as infinite.
I am not a programer at Agilent and I just wanted to say that based on my experience, I get better results with the use of internal/ground reference ports for structures where the substrate's size matters ... but maybe just a bad habit of mines.