A novel phase encoding technique exploting linear or circular polarization

The phase response of an High-Impedance Surface (HIS) to an incident plane wave linearly polarized is employed in order to realize a chipless RFID with phase-only encoding. The encoding is obtained by using stubs of different length applied to each single loop included in the unit cell. The information is encoded in the difference between the TE and TM phase response of the tag. Possible improvements of the proposed structure in terms of increased bit capacitance and robustness are also investigated.