minimun trace width for 50 watts on FR4 board

[winglj]

Hi, everyone. I have a question about the minimum copper trace width for 50 watts on a FR4 board with about 62mil thick. Are there any calculation formula for the estimation. Thanks.

 

[PaulHolland]

Hi, 50W is not we need to know... How big the current is more interesting.. I assume its a DC application or maybe AC ?.. We are not talking about RF are we ...

 

[winglj]

Hi, PaulHolland. Thanks for your reply. Actually I am sorry about that I do not mention the operation frequency is at 2.4 GHz, so it is in RF..... Any idea about how to calculate the currents at this range?

 

[PaulHolland]

OK. 2.4 GHz.. firstly your using the wrong PCB at this frequency since it will give high loss @ 2.4 GHz if your tracks are long. The second thing is that currents are not going through the coper but at the edge between coper and substrate and last your tracks should have a width that is giving your 2.4 GHz a 50 Ohm transmission line at standard FR4 62 mill that is about 100 - 120 mill wide. Better use RO4350 PCB at this frequency !.

 

[FvM]

Just to get an idea. How would you estimate the damping due to substrate losses of a FR4 4" length 50 ohms transmission line at 2.4 GHz?