I was reading a few forum posts regarding the (lack of) a tapered line. One person suggested that a arbitrary zone could be made which tapered as desired. This is a valid method, but it has the disadvantage of requiring you to redraw the tapered section EVERY time you need one, which I took to be a burden, particularly if you move components and redesign as often as I do.
I’ve had some success making a New Footprint which is a SMD Trapezoid which is able to be tapered. This technique still requires some work, but I am able to make a decent tapered section.
The Footprint has a single pad.
X=2mm Y=1mm which sets the basic size
The Trapezoid Delta of 0.4 establishes the Taper. If you study the tapered pad the 0.4 is the increase on the wide end and the decrease on the narrow end. The limit is that the narrow end can not go to 0 or negative and this single parameter controls both.
A Shape Offset of 0.75 places the trace attachment point more toward the wide end.
Several such footprints maybe required to address the various board thicknesses and other params.
When doing a PCB layout with a 50 Ohm line, it is necessary to add the Tapered Section (TS) and place it with the narrow end very near the device pin. A short thin trace connects to the device pin, such as a QFN.
Since the TS is not on the schematic (therefore netlist), you have to manually edit the TS params and specify the appropriate NET. Then a wider trace can be added to be the 50 Ohm line. Also note that I added an X offset so the trace attachment point is NOT the center of the TS. Otherwise the rounded end of the wide (50 Ohm) trace will splatter over the TS. Again, this would benefit from more fine tuning.
btw - If you don’t Edit the TS params, it will still be on the copper layer but the DRC will be seriously unhappy reporting a UNconnected trace. I also LOCKED the TS so that if you reread the netlist, the TS is not discarded as it doesn’t appear in the netlist.
This isn’t perfect, but it is not a total kloooodge either. When viewed at 1:1 scale, it looks darn good and is way less painful than making a zone each time (I think).