A
Andy
Guest
Hello:
I want to lay out a couple of traces on the FR4 PCB, to provide a
transmission line of specific impedance for a differential-mode signal.
The impedance calculation formulas that I have found so far, for the
common-mode and differential impedance, concern the traces with the
ground plane underneath. I think I don't want the ground plane
underneath, to minimise the common-mode capacitance, and I am looking
for the formula for the coplanar traces on one side of the PCB, with no
metal (copper) in the other PCB layers in the vicinity of the trace.
Can somebody help?
Thank you.
-- Andy
I want to lay out a couple of traces on the FR4 PCB, to provide a
transmission line of specific impedance for a differential-mode signal.
The impedance calculation formulas that I have found so far, for the
common-mode and differential impedance, concern the traces with the
ground plane underneath. I think I don't want the ground plane
underneath, to minimise the common-mode capacitance, and I am looking
for the formula for the coplanar traces on one side of the PCB, with no
metal (copper) in the other PCB layers in the vicinity of the trace.
Can somebody help?
Thank you.
-- Andy