Differential Transmission Line Loop for RFID Reactive Near-Field Coupling

作者：Frank Markus^*; Thorsell Mattias; Enoksson Peter

来源：IEEE Transactions on Microwave Theory and Techniques, 2018, 66(5): 2141-2153.

DOI：10.1109/TMTT.2018.2811484

• Delta Gamma-value
• differential transmission line loop (DTLL)
• power gain
• radio frequency identification (RFID)
• reactive near field (RNF)
• RFID inlay
• ultrahigh frequency (UHF)

The differential transmission line loop (DTLL) as an efficient reactive near-field coupling element for programming of radio frequency identification (RFID) inlays is proposed. It is validated, with simulations and measurements, that the differential excitation and the presence of a ground plane are fundamental properties for high performance in coupling while providing high electromagnetic isolation. As a proof of concept, super elliptical loop geometries as coupling elements are investigated for a number of commercially available inlay geometries. From simulations of the DTLL and inlay antenna, coupling efficiencies higher than 80% are predicted. Measurements of the Delta Gamma-value indicate a nonlinear input impedance with power, and verify the high values of simulated coupling efficiency. The threshold power levels read from interrogator are below 5 dBm, which are considered as very low in inlay encoding, and hence show that the DTLL is a promising candidate for efficient RFID programming in the reactive near field.

• 出版日期2018-5