S parameter G-S-G layout not grounded

[mhma]

Hi guys,

What happened in passive device s-parameter measurement if the ground pad (GSG) in the layout not connected to the ground (for example some layer is missing)

Thanks in advance

 

[khouly]

ur GND path is not connect ,
so expect very strange S parameters !!!!!
u can simulate it on any EM tool ,
I have simulated GSG PADS with momentum and t gave very nice results

Khouly

 

[mhma]

Would it still possible to get the device s-parameter after de-embedding?


Thanks

 

[ge]

khouly is right. Expect strange results. The amount of unpredictability would depend on a large number of factors, frequency, ability to characterize other parameters, etc. For a simple attenuator, yes. A more complex circuit...

 

[mhma]

it is a spiral inductor test structure. I forgot to connect the ground pad to the ground.

 

[volker_muehlhaus]

it is a spiral inductor test structure. I forgot to connect the ground pad to the ground.

Do you have a connection between the port 1 / port 2 grounds?

 

[mhma]

No connection

 

[volker_muehlhaus]

No connection

Then it will be very difficult to interpret measurements.
Your ground pads will have some capacitive coupling to the substrate, but that current return path in the substrate is high impedance and will dominate the overall results.