LNA design in ADS momentum?

[mashhadiDRA]

Can any one plz guide me through teh process of designing an LNA in momentum...or that if I have a schematic made ..what steps would i need to follow for the onjective acheivement i.e. LNA?

thnaku
regards.

 

[alperuslu]

In momentum you can not simulate lumped elements such as capacitors,inductors etc. except microstrip based components like interdigital capacitor...

First you create the schematic and use tline discontunities where the discontunity occures. Then you simply click generate/update layout to generate layout.Look layout if there is a problem try to fix it in layout window then simply click generate/update schematic. If you want to design lna with real components select distributed elements from vendor libraries generally they comes with artwork so in layout windows you can see them.After you generate layout , delete lumped components and add ports to their connection points.Define substrate parameters from momentum>Substrate>Create/Modify. The next step is to generate layout component to cosimulate lna.To do this click Momentum >component >create/update and define your frequency range.After creating layout component open a new schematic design and place your layout component.Then add your lumped elements and place S parameter measurement.Then simulate it.Thats all.

I attached some pictures that summarizes the process.

Good Luck,
ALP

1)Lna Schematic


2)Layout from Schematic(Generate Layout)


3)Layout for Momentum


4)Cosimulation

 

[nassim1]

That's right, you have to follow as alpuslu explain it, cause it's only the solution for using circuit simulation with lumped element. from schematic to layout then from layout to schematic by creating component in layout.
You will not find a manual for that so you just follow the way..

 

[mashhadiDRA]

Hi Alpuslu!
Thank you so very much for the huge effort u’ve made. After looking at the figures that u attached, I realized that there are a lot of things I needed to look into before jumping to momentum step. I was confused about a few things which are as follows:
What exactly do you mean by a discontinuity?
At what stage do I mention the layers? Is it in the MSUB? I have no concept about how to segregate layers. Please guide me on that too.
How do you get a layout like what you have? Your layout has a microstrip surrounding the whole design. I do not know what the purpose of it is. Is it for vias? At what stage do we add vias? What about the grounds used in the schematic?
Lastly I get a warning that ‘bond pads overlap each other’.
I have attached the design and the layout.
Thank you so much. Your reply had guided me quite a lot in this regard.
Regards.

 

[alperuslu]

I meant transmission line discontunity for example if you have MLin element and you want to connect open circuit or short circuit parallel transmission line to it you should use MTEE or etc. discontunity to connect it.

Yes the microstrip that surround the design is for ground plane.You can delete grounds in layout window and you can connect them with ground plane that has vias.When you add SMT pad into your schematic you should set pad size. it depends on which size component you use. In datasheets manufacturers defines the pad size.

To add vias in layout window change current layer to vs,hole and simply draw circle.In schematic window you can use via hole component instead of this operation then convert schematic to layout.

MSub components defines the dielectric material that you use.I could not see your pictures clearly.If u repost it with better resolution than it i can commend.

 

[mashhadiDRA]

Hi,
In this figure the highlighted portion is the transistor footprint. I was able to improve the layout after that to this version. Now following points I need to clear:
You can see the grounds placement; do I simply replace them by “via_gnd”?
Is there any specific way of adding the surrounding conductor layer or is it simply by adding and specifying the dimensions of transmission line? Will I need to change my current layer also?
What would be the sequence of defining layers?
I generate the layout.
Then I change my current layer to vs, via
There I replace my grounds with via_grnd.
Please could you rite in point form all the steps you yourself would take for preparing a perfect layout of an LNA for momentum.
I shall be grateful to you.
Thankyou.