RFID chip input signals

If you drive two inputs differentially, they are differential.
That's all.

There's only one signal which is the antenna. Whether
it is ground returned or a dipole type feeding a differential
amplifier & power-take block, you'd have to ask your
radio / antenna guy.

My only exposure to RFID was single ended and over a
decade ago. What today's art is, you would have to
study.