An early concept of the Solar Probe (reborn as Solar Probe Plus then Parker Solar Probe) used parabolic antenna with a heat-resistant nadir facing side to double as a heat shield.
While sourcing this answer on Solar Probe Plus's mission design, I found this excerpt which makes it seem like the development of the antenna got much further than I originally thought. For example, it shows a prototype of the antenna's feed assembly.
Was a full-scale prototype made for the Heat Shield/Antenna?
Or did the antenna not get past the component-prototyping stage? Alternatively, have there been further feasibility studies since the concept was dropped for Solar Probe?
Photographs or diagrams beyond those shown in the link above would be ideal.