How to simulate in ADS layout using ground polygon?

To do simulate proximity effects of groundplane close to microstrip lines within ADS you would need to use EM simulation with Momentum (planar EM) or EMDS (3D EM). Regular circuit simultor models will not be able to characterize these effects.

Yes, i know. I simulate my scheme with Momentum. But i don't know how to add ground polygone. Look at the picture.

You should create an extra ground shape/layer and associate a port for this layer.Then you can simulate in schematic view by grounding this port.

Thank you BigBoss for answering. But could you explain it in details? may be you have some references. I try to read a help of ADS - momentum, but i haven't undestood in full. I draw a polygon and connected a port, type of the port was reference ground. And i have an error: " Ground Reference port P3 must be associated to another" What next should i do?

Add your ground polygon on say cond2 layer and your microstrip is at cond layer, Now add ports to your micrsotrip on cond layer on edges, then add two more port just beneath previous ports on cond2 layer which will be attached to your ground,
Now go to port edditor and select the ports on cond2 layer one by one, and select the port type as ground refference and associate them to the port one above it, thats it (keep the port type on cond layer as single port)

Change the substrate accordingly and remove the ground from there,.
substrate will be like this

air
------cond
subs
-----cond2
air

Imfarhan1 . Thanks for answering. I would like to amend my question. I have to make the ground polygone on cond. If i will do as you have told, then cond2 will be ground. But i need the ground on the cond.

PS:
I want to have such structure

air
-----cond <------- here I need to have the ground polygone on this layer.
subs
-----ground

How do you intend to create the groundplane connections on the actual board? You have to do the same thing for Momentum.

Your simple illustration would have only two ports, one on each end of the microstrip line. The ground plane can then be drawn as a polygon on the same cond layer as the microstrip lines as required.

Now, assuming you are going to have through connections within the ground plane polyogon to connect to the ground conductor on the back of the board, draw 'via' structures within the ground plane polygon as required. Draw these 'vias' on a different layer, maybe hole, and then map the hole layer as a VIA to the substrate between cond and GND.

Your substrate setup should then look as follows:

Free_Space
------- -STRIP- cond
Substrate |VIA| hole
///// GND ////

Ok thats not a problem just map layer accordingly, Like the ports declayered as ground will be on cond layer, and they are reffering to ports on cond2 layer.
substrate will be like

air
---------cond2 (MS)
subs
---------cond (gnd)
air

In short just repeat whole process by swapping cond and cond2 layer.
Hope it answered your question

Thank you all. And thank you RealAEL. I have simulated my project in ADS layout and have a good result. I used the ground via for grounding microstripe lines.

I am a beginner for momentum

I have a structure in momentum

air
Cond
FR4 VIA-Hole
////GND////

I just wanted to make sure if i use the viagnd structure it will link to the ground layer.

Also how does the simulator determines the size of gnd plane. I am assuming it lays it to cover entire strucure above?

Thanks

@sajan09
Any layer maped as via acts as via it can be other than via, hole. diel etc
but make sure what ever layer you map as a via should have a structure in layout. let me explain
if you want to add a via between cond layer and ground
make your strip on cond layer
make a polygon on anyother layer say hole
now go to material editor and define it like this

cond
------hole
GND

second part
For predefined GND the momentum considers the infinite ground plane NOT only underneath the design so if you need only under you design you have to define it by your self
hope that answered you question

@sajan09

The gnd when connected using through holes(vias) act as gnd.

In momentum the Gnd specified is considered as a infinite gnd plane. If u want to have a realistic scenerio u can use box structure.

Thanks for your replies

The question I now have is

If i have to model a 2 layer PCB. Top layer for signal routung and bottom layer ground. Can I use momentum structure

cond
diel VIA(hole)
/////GND////

or i should do

cond
diel VIA(hole)
cond2

and then attach ground reference ports on the cond2 layer

Well, if u have continous gnd(w/o discontinuities) without in the 2nd layer u can go with the first approach.

hi ...i have to model a 3 layer PCB.....my layers should be in the following way....
free space
cond1(micro strip)
substrate
ground
substrate
cond2(microstrip)
free space
how to model this in ADS momentum and i also want coupling between cond1 and cond2 .....how to define the layers.....

Hello all!
I have a question:if I only need a single layer,which means there's no GND on layer 2,I just have microstrip and GND on same layer,to avoid floating the GND,I can connect the GND of this module to the board through RFcable.Then how can I set the momentum?

Best regards!

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