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Karan paliwal , 03-02-2026, 11:49 AM

Hello,

I need some help regarding 50Ω impedance matching in my PCB layout.

I am trying to achieve 50Ω impedance using the Saturn PCB Toolkit. I have two different layout conditions. When I calculate the track width in Saturn PCB Toolkit, it shows 50Ω impedance correctly.

However, my concern is:
If I place a matching component on the same RF track, the pad width of the component is larger than the calculated 50Ω track width. In that case, how should I maintain 50Ω impedance for that section of the track?

Since the track becomes narrower compared to the matching component pad, I am not sure how to manage this properly in Saturn PCB Toolkit. Is there any alternative method or recommended approach to handle this situation?

For proper clearance and better understanding, I am attaching images for both conditions along with the PCB stack-up.

Please help me understand how to manage impedance in this case.
@Robert Feranec @QDrives

Karan paliwal , 03-02-2026, 11:54 AM

PCB stackup

Karan paliwal , 03-02-2026, 12:05 PM

When placing a matching component, if the pad size is large, the clearance between the RF track and GND increases locally. In this condition, how does the impedance remain matched?

In impedance calculators, we enter a fixed clearance value from GND. However, in the actual PCB, due to the larger component pads, this clearance changes. How does impedance matching remain valid in this situation?