rich wrote:
My antenna designs do not need a balun because I use
a modified version of a feed called a Gamma match that feeds the
antenna at the fifty-ohm point and automatically balances the currents
on the elements."

I don't think a gamma match is considered "balanced" since it only is on
one side of the antenna "dipole". A "Tee" match is more "balanced" as
it acts on both legs of the antenna poles.

That said, a quarter wavelength "whip" antenna for the transponder
frequency acting against a ground plane requires no balun or matching
circuitry.