Spatially Confined UHF RFID Detection With a Metamaterial Grid

The confinement of the detection region is one of the most challenging issues in Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) systems. Here, we propose a new paradigm to confine the interrogation zone of standard UHF RFID systems. Our approach relies on the use of an all-planar metamaterial wire grid to block the radiation field (i.e., the far-field) of the reader antenna, and thereby obtain a spatially well-confined detection region in the near-field. This solution is analytically and numerically investigated, and then experimentally verified through near-field and tag-reading measurements, demonstrating its effectiveness and robustness under external perturbations.