I have demonstrated a Carbon Fiber Yagi.
I did fudge a little bit, and the first inch or so of the driven elements was
brass tubing. Hard to solder the coax to carbon fiber.
Carbon fiber is electrically conductive and behaves just like Aluminium
Carbon Fiber Rods make nice Yagi Elements.
Nearly 50 years ago the 10 foot dish used on the Voyager spacecrafts were made
out of Carbon Fiber. They were taken to the antenna range ..... and passed specs.
As a weight savings there were NOT metalized.
Just got some 3D printed clips for the Arrow booms. These are designed to hold
an 11 element 1269 MHz Yagi 45 deg to the 145 and 435 MHz elements adding L-Band.
73 Kent WA5VJB