No abstract

The performance of an ultra-high-frequency RF identification (ID) system operating at 869 MHz, intended for the ID of persons in both indoor and open areas, has been validated using the propagation models, as well as the series of practical measurements. A two-ray propagation model and the 3-D ray-tracing model were used for calculations of all important system parameters in open and indoor areas, respectively. For the application mentioned above, a novel (electrically small and, at the same time, low-profile) wearable TAG antenna was designed. It was used in order to carry out the necessary tests as well. The antenna in question is based on an artificial-like surface. The latter provides an important screening effect and avoids detuning. Another virtue of the surface used is represented by the fact that it ensures the minimum loss of the antenna efficiency (resulting from the presence of a nearby human body). The simulations and measurements show that the optimized system can guarantee a reliable ID at distances up to 9 m in open areas and up to 16 m in corridors.Index Terms-Artificial surface, electrically small antenna, identification (ID) of people, loop antenna, RF identification (RFID) system, TAG antenna.

No abstract

We propose a novel chipless RFID tag composed of topologically modified uniplanar U‐folded dipoles with inclined arms. This topology reduces the interelement mutual coupling and provides a significantly better amplitude uniformity and frequency stability of tag RCS response when logical “0” is coded by removing particular scatterers from the array. Simultaneously, it provides a higher encoding capacity in unit frequency range than the arrays composed of original U‐folded dipoles with parallel arms, yet at the expense of small RCS magnitude reduction.© 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2723–2725, 2016

Novel type of extremely low-profile low-dielectric constant substrate antenna, based on two-element slot-coupled shortedpatch structure for UHF RFID applications has been developed. We use two different methods for tuning the complex input impedance-dipole excitation and direct excitation with tuning slots. Both credit card-sized antennas exhibit the antenna efficiency better than $50%, irrespective of whether they are placed in free space or enclosed to either metallic or human body.