Keysight momentum hangs while EM simulation
I am trying to simulate a balun in TSMC65nm process using momentum. Smaller baluns simulate well. But when balun is large it hangs. Is there any solution?
Should I reduce layers in the substarte by calculating average permitivity?
I am using windows 7 and RAM is 12GB.
It depends on the size of your problem. Since you are trying to simulate an on-chip structure with lots of layers and vias, even on high spec servers, there is a good chance that your simulator will hang. I am not mentioning dummy metals which if you add them to your simulation, it will become a nightmare.
As you said, the solution is trying to simplify your structure. In layout, just use the layers that your balun is placed on them (you should also have ground which might be on M1). Calculating the effective dielectric constant for merged layers is not as simple as it appears at first.
Solving this problem needs experience and intuition.
Hi Hamid, Thank you for your reply. I made the following changes:EM setup>options>physical model> global>thick conductor=2D >via=3D
It made things faster. I kept via as 3D but metals as 2D. Is it too risky for 2.4GHz application.
Further, I am using this formula e=(e1*h1 + e2*h2 + .....)/(h1+h2+....) to find effective weighted mean permitivity . Is that alright?
2.4 GHz is considered low frequency at least in my opinion but for metal layers I would use thick conductor option. If you have lots of vias, then consider merging some of them while you keep in mind that there shouldn't be any horizontal current flowing through vias.
For effective dielectric constant consider layers as series capacitors and then find the relevant value.
Thank you very much. Your suggestions have been helpful. One more question: Momentum results in two datasets i.e. MomRF and MomRF_a. What are the differences?
I believe "a" is for adaptive response. Use the one which has "a"