That is ingenious! Just haul raw materials to orbit, 3D print your antenna structure, and let solar UV do the curing. You can build structures larger than the rocket fairing.
How long before they can print solar cells for power generation. I worked for a company once that was able to print solar cells.
So from those pics it looks like the extruder oozes the resin on a rotating base in ever expanding circles. The resin would have to be sticky enough to attach to the previous layer. Then the rotation would have to be slow enough for the last layer to have been cured before the next layer was applied. And if the resin had a metallic content it would work as a signal reflector.