Space-filling curve RFID tags

Abstract

A completely passive Radio Frequency Tag is proposed, utilizing the scattering from electrically small but resonant inclusions. When placing these space-filling curve inclusions in an array and scaling each element within the array such that each element has its own separate resonant frequency, a radio frequency barcode can be developed from the Radar Cross Section of the array. The narrow bandwidth inherent to such inclusions can be helpful in packing the overall signature into a relatively small frequency spectrum. Such Radio Frequency Tags may have potential use in some applications of Radio Frequency Identification Systems.

Multiresonator-Based Chipless RFID System for Low-Cost Item Tracking

“…The received and transmitted signals are cross-polarized in order to achieve good isolation between the two. Due to these differences, we believe to have achieved less mutual coupling effects, greater number of possible bits, and easier encoding than reported in [7] and [8].…”

“…This represents a novelty in data encoding and data extraction when it comes to chipless frequency-signature-based RFID systems. Other frequency-signature-based chipless RFID systems are based on examining and encoding the magnitude of the signal [7], [8], while this system encodes data into both phase and magnitude, thus enabling complete information for decoding the frequency signature (magnitude and phase) where phase is preferred for greater reading ranges and accuracy.…”

“…We have reported preliminary results on our system, but only focusing on the proof of concept [13]. The main differences between our system and the ones reported in [7], [8], and [13] are that we encode data in both amplitude and phase, show the possibility of designing a UWB chipless tag, and that the system is not based on radar cross section (RCS) backscattering, but on retransmission of the interrogation signal with the encoded unique spectral ID. The received and transmitted signals are cross-polarized in order to achieve good isolation between the two.…”

“…Fully printable chipless RFID tags have been reported using space-filling curves [7] and capacitively tuned dipoles [8]. The space-filling curves require considerable layout modifications for data encoding, while capacitively tuned dipoles could have undesired parasitic mutual coupling effects and size limitations restricting efficient data encoding.…”

High data density and capacity in chipless radiofrequency identification (chipless-RFID) tags based on double-chains of S-shaped split ring resonators (S-SRRs)

“…Concerning chipless RFID tags, the interest in this work, transmission lines loaded with multiple resonant elements, each tuned to a different frequency, have been proposed as multi-resonant frequency domain based tags [31][32][33][34][35][36][37][38][39][40][41][42][43][44]. In such chipless-RFID systems, the interrogation signal is a multi-frequency sweeping signal covering the spectral bandwidth of the resonant elements, and the ID code is inferred from the dips present in the frequency response (retransmission based tags) [31][32][33][34][35][36][37] or in the radar cross section response (backscattered tags) [38][39][40][41][42][43][44], caused by the resonant elements. Therefore, the presence or absence of dips at predefined frequencies (each one corresponding to a different bit) is associated with the logic state '1' or '0'.…”