I don't know enough about the reflector. If it works like a boat's radar reflector, an 20 cm reflector would have a equivalent cross section as a metal sphere

I don't know enough about the reflector. If it works like a boat's radar reflector, an 20 cm reflector would have a equivalent cross section as a metal sphere with an area of about 30 square meters. I mean the goal of a radar reflector is to send radar signals back to their source, they are super effective. They don't really work like antennas generally, but the pictures of the F-35's reflectors do not look typical, or like a boat's radar reflector, and I have no idea what principle they use.