Space-Filling Curve Radio Frequency Identification Tags

Two different concepts for the use of resonant space-filling curves (SF-curves) elements as RFID tags are proposed. In the first concept the space-filling curve geometries such as Hilbert and Peano curves are studied with respect to the creation of an ultra-passive type of RFID in which an array of space-filling curve elements, scaled to resonate at different and particular frequencies, are used to provide a backscattered signal, in which information can be embedded. Using both numerical simulations and RCS measurement, it is shown that these electrically compact resonators could produce relatively large scattered fields over an inherently narrow frequency band at their corresponding fundamental resonant modes. The performances of these tags are also investigated when placed near a typical inventory objects, such as paper rolls. In the second concept, an SF-curve antenna is used above an SF-curve high impedance surface to develop an RFID tag that is well-suited for tagging of conducting objects.