I may not have fully understood your request… But, let’s say you know the dimensions for the antenna’s shape and want to make copper traces of them, there are a handful of ways to do it.
The way you do it will dictate the usefulness of the result and the required next steps.
Others can provide info on Plugins to use Eagle files.
Drawing Options include:
#1) Draw the traces in PCBnew
#2) Draw shape in PCBnew on a layer such as Silk, Dwg, Eco…etc and convert them to desired Cu layer
#3) Draw shape in your favorite drawing program, save as DXF or PNG.
DXF can be imported directly into PCBnew (and Footprint editor). PNG can be loaded into the BMPtool (in Kicad’s main panel), then exported as .MOD (that makes it a Footprint)
The choice of options above dictates the next steps…
Can trace Cu over the DXF or PNG.
Example shows using a screenshot (thus, a PNG) loaded into the BMPtool and exported as .mod. Then, .mod loaded into PCBnew and traced in Cu layer (I did not fuss with trace-width but, you get the idea). I could have converted it to Cu instead of tracing.
If drawing exact geometry in external program and saving as DXF, you can import into PCBnew and convert to Cu layer…
There are many posts on doing that…
