Adding elements of the same length to a dipole does not produce much
benefit, while in contrast adding more elements as radials to a quarterwave
vertical antenna produces a lot of benefit. Many books claim that the
radials of a quarterwave vertical antenna form an image. It is said that the
greater the number of radials, the more 'perfect' this image is and the
greater the efficiency. In contrast, adding elements of same length to
dipole increases bandwidth and creates an unusual radiation pattern e.g. fan
dipole.

2 theories on vertical groundplane antenna a

1) Radials reflect radio wave emitted by vertical radiating element. Radials
form a ground plane to reflect radio wave. Image theory applies where
radials form a 'mirror' image.

2) Radials are simply conductors carrying current, and radiate accordingly.
But they are placed and fed so this radiated wave nearly cancels. Radials do
not form a flat metal conductor many wavelengths in diameter. Radials do not
reflect the wave emitted by vertical. The radials are too short to reflect
the wave radiated by vertical.

With elevated radials, the radials are normally a quarter wavelength long.
If the radials are proper current carrying conductors instead of a metal
reflector, the radials will transform the high impedance at open circuit end
to a low impedance at base of antenna. Low impedance means antenna is
current fed. If the radials are made a half-wavelength long or longer, does
the impedance and SWR of the antenna stay the same?

Are there any tests to prove which of the above 2 theories is right?