I’m trying to create a 50 ohm controlled impedance with coplaner wave guide and I’m wondering how do I create the gap width between my traces and pads with the copper pour? Is there any tools for that or I’ll have to manually draw floating traces between the copper pour and the traces? I’m trying to have a 0.5mm gap between my traces and copper pour.
I don’t know much about HF stuff, but for me the obvious andwer would be to set the clearance setting of the zone:
But you have a few millimeters of track between your SMT footprints. How do you make a controlled impedance of such short sections? Maybe it helps a bit to use SMT parts that have the same width as your tracks, or set your tracks to the same width as the pads of your SMT footprints, but I don’t know if that actually does something or is just visual.
I agree with Paul, this is such a short width, it likely doesn’t need careful impedance control. I think the rule of thumb is if the trace is less than 1/32 of the wavelength of your max frequency an impedance mismatch won’t impact performance.
KiCad’s libraries have rounded corners for pads of SMT parts for several years now, which makes me wonder what KiCad version you are using and/or where those footprints come from. Not saying anything would be wrong, just curious.
I’m using 5.1.10. It’s from a library we created years ago and we just continue using those footprints. I heard rounded corners for pads are better for manufacturing, is that true? And what will be the typical corner radius for those rounded pads?
It is and the original IPC-7351 requested rounded pads (actually stadium but that’s different ). eCAD software were unable to make such rounded pads so rectangle stuck.
The pads are always rounded anyway due to the etching process. Rounded stensil helps with the paste
The typical radius is 25% iirc