Jaroslav Havlicek

Improvement in Robustness and Recognizability of RCS Response of U-Shaped Strip-Based Chipless RFID Tags

This letter presents significant improvement in robustness and recognizability of radar cross section (RCS) response of the two topologically rearranged 20-bit U-shaped strip-based tags for spectral signature-based chipless RFID systems. The space rearrangement of individual tag scatterers in the array reduces the interelement mutual coupling and, thus, significantly enhances the frequency and amplitude robustness of their RCS. In comparison to the original arrangement of scatterers, the measurement of tags designed for 2-4-GHz frequency band showed a significantly improved homogeneity of the RCS curve, which results in a more reliable recognition of coded information.

A comparison of two ways to reducing the mutual coupling of chipless RFID tag scatterers

This paper presents two ways to reduce the mutual coupling between the resonators of the RFID chipless tags. This reduction significantly improves the uniformity of the RCS response of the tag over the operational frequency range from 2 to 4 GHz. The first modification to the tag layout is based on an inter-element rearrangement of the array elements. The second layout modification is based on narrowing the strip width and tapering the longitudinal dipole arms toward the open end. Significantly improved homogeneity of the RCS response in comparison with the original array of folded dipole scatterers was confirmed by simulation and by measurements of 20-bit chipless RFID transponders. The second modification further improves the frequency resolution, which may consequently provide higher encoding capacity in a unit area, but at the expense of a decreased RCS response.

Capacitively loaded dipoles for chipless RFID transponder

This paper proposes a novel uniplanar capacitively loaded dipole-scatterers as building elements for chipless RFID tags with frequency domain coding information. These elements are compared with the known structures in terms of quantities which are crucial for read range (radar cross-section), coding bit capacity (resonance bandwidth), and electrical size. Most suitable type of scatterer was arranged into a 5-bit tag, manufactured and verified by measurement in anechoic chamber.