Momentum three "free_space" in substrate layers

Hi, all,

I have set the boundary for the top and bottom free_space layers to open. Since I need to simulate the power transferring from one antenna to another in free space. I need a third "free_space" layer between my two antennas. Hence I defined three "free_space" (freeSpace_top, freeSpace_between and freeSpace_bottom) layers inside "Substrate layers" tab.

1) In "Layout layers" tab, I managed to set two "strip" and two "free_space" (freeSpace_top and freeSpace_bottom) in "layout layers". However, when I try to define the "free_space" between these two antenna, the "material" list only contain "conductor". It seems that momentum won't allow me to have the third "free_space" layers! Why is that so? Should I use VIA in between istead of freespace?

2) Also, why does momentum ask for the material thickness for my "freeSpace_between" twice? I need to input the information twice in both "substrate layer" and "layout layer" tabs. For "freeSpace_top" and "freeSpace_bottom" it disabled any settings in "layout layer" tab, but for "freeSpace_between", "strip_cond" and "strip_cond2", I need to input the material type, conductivity, thickness information, etc.

Thank you very much for explaining to me!

Hi grit_fire,

1) you can only have 2 open boundaries as "free_space" is infinite. I think you also want to define the distance between you 2 antennas.

2) you have to define a dielectric layer between your 2 antennas that acts as an air layer with a finite thickness (the distance between your antennas).
I don't know at which frequency you work and what is the distance between your 2 antennas, but I guess that if you are interested in far field the simulation will be time consuming.

Hope it helps,

JB

Hi, JB,

Thanks for the reply!

1) How should I map the dielectric layer in "Layout layer" tab? Should it be "die1"? Also, in the left list, should I make the "air layer" VIA or something? (After I select "die1" on the right list, on the left, it will ask me if i want to set it as VIA or not).

2) I am doing near field simulation. Can momentum do that?

Thank you!

You have to reach this stack-up to build up your system:
* in "Substrate Layers" tab:
Freespace_top
diel2
air
diel1
Freespace_bottom

* in "Metallization Layers" tab:
Freespace_top
-----
diel2
----- Strip cond2
air
----- Strip cond
diel
-----
Freespace_bottom

Your antennas (without ground plane as you wish) will be on metal cond and cond2 on substrate diel and diel2. The layer air will be the air gap between your antennas (its thickness=distance between antennas).
Remember that you can edit/rename/add/remove any layers in Momentum in the "Layer Editor" (Options - Layers).
I already successfully simulated coupling between open-ended T-lines through substrate thickness with Momentum, but I don't know exactly what your system looks like (frequency, gap between antennas, ...).

Hi, Thank you!

In this way, I find that I am not able to set anything for die1 and die2 in the "layout layer" tab. I basically need to set every parameter for die1 and die2 in "substrate layer" tab. Is that correct?

sorry, the names diel and diel2 are by default reserved in Momentum: when you go to Options - Layers you can see that they already exist.
I should have said something like sub and sub2.

Hi, Thanks!

I have changed the name. In fact, my question is: I defined the conductivity, permeability and permittivity in the "substrate layer" tab for sub1 and sub2. Then in "Layout layer" tab, do I need to define anything for sub1 and sub2, too?

Substrate Layers tab ist to define your stack-up of dielectric layers and the Layout Layers tab to map the metalization/thin-layers resistors/vias through substrate.
So you then have to map (strip) cond and cond2 on sub and sub2.

Hi, just to make sure I understand what you meant. By saying "map the metalization/thin-layers resistors/vias through substrate.", did you mean to determine the position of cond1 and cond2 by place them on top of sub1 and sub2 respectively? and I don't need to set anything for sub1 and sub2 in "layout layer" tab (i.e. set the model, thickness, material)?

Thank you!

---------- Post added at 00:26 ---------- Previous post was at 00:10 ----------

Another question is: How do I know if my system is under simultaneous conjugate matching when being simulated? Thanks!